Major admixture in India took place ~4.2-1.9 thousand years ago (Moorjani et al. 2013)

A new paper on the topic of Indian population history has just appeared in the American Journal of Human Genetics. In previous work it was determined that Indians trace their ancestry to two major groups, Ancestral North Indians (ANI) (= West Eurasians of some kind), and Ancestral South Indians (ASI) (= distant relatives of Andaman Islanders, existing today only in admixed form). The new paper demonstrates that admixture between these two groups took place ~4.2-1.9 thousand years ago.

The authors caution about this evidence of admixture:

It is also important to emphasize what our study has not shown. Although we have documented evidence for mixture in India between about 1,900 and 4,200 years BP, this does not imply migration from West Eurasia into India during this time. On the contrary, a recent study that searched for West Eurasian groups most closely related to the ANI ancestors of Indians failed to find any evidence for shared ancestry between the ANI and groups in West Eurasia within the past 12,500 years3 (although it is possible that with further sampling and new methods such relatedness might be detected). An alternative possibility that is also consistent with our data is that the ANI and ASI were both living in or near South Asia for a substantial period prior to their mixture. Such a pattern has been documented elsewhere; for example, ancient DNA studies of northern Europeans have shown that Neolithic farmers originating in Western Asia migrated to Europe about 7,500 years BP but did not mix with local hunter gatherers until thousands of years later to form the present-day populations of northern Europe.15, 16, 44 and 45

This is of course true, because admixture postdates migration and it is conceivable that the West Eurasian groups might not have admixed with ASI populations immediately after their arrival into South Asia. On the other hand, a long period of co-existence without admixture would be against much of human history (e.g., the reverse movement of the Roma into Europe, who picked up European admixture despite strong social pressure against it by both European and Roma communities, or the absorption of most Native Americans by incoming European, and later African, populations in post-Columbian times). It is difficult to imagine really long reproductive isolation between neighboring peoples.

Such reproductive isolation would require a cultural shift from a long period of endogamy (ANI migration, followed by ANI/ASI co-existence without admixture) to exogamy ~4.2-1.9kya (to explain the thoroughness of blending that left no group untouched), and then back to fairly strict exogamy (within the modern caste system). It might be simpler to postulate only one cultural shift (migration with admixture soon thereafter, with later introduction of endogamy which greatly diminished the admixture.

The authors cite the evidence from neolithic Sweden which does, indeed, suggest that the neolithic farmers this far north were "southern European" genetically and had not (yet) mixed with contemporary hunter-gatherers, as they must have done eventually. But, perhaps farmers and hunters could avoid each other during first contact, when Europe was sparsely populated. It is not clear whether the same could be said for India ~4 thousand years ago with the Indus Valley Civilization providing evidence for a large indigenous population that any intrusive group would have encountered. In any case, the problem of when the West Eurasian element arrived in India will probably be solved by relating it to events elsewhere in Eurasia, and, in particular, to the ultimate source of the "Ancestral North Indians".

It is also possible that some of the ANI-ASI admixture might actually pre-date migration. At present it's anyone's guess where the original limes between the west Eurasian and ASI worlds were. There is some mtDNA haplogroup M in Iran and Central Asia, which is otherwise rare in west Eurasia, so it is not inconceivable that ASI may have once extended outside the Indian subcontinent: the fact that it is concentrated today in southern India (hence its name) may indicate only the area of this element's maximum survival, rather than the extent of its original distribution. In any case, all mixture must have taken place somewhere in the vicinity of India.

A second interesting finding of the paper is that admixture dates in Indo-European groups are later than in Dravidian groups. This is demonstrated quite clearly in the rolloff figure on the left. Moreover, it does not seem that the admixture times for Indo-Europeans coincide with the appearance of the Indo-Aryans, presumably during the 2nd millennium BC: they are much later. I believe that this is fairly convincing evidence that north India has been affected by subsequent population movements from central Asia of "Indo-Scythian"-related populations, for which there is ample historical evidence. So, the difference in dates might be explained by secondary (later) admixture with other West Eurasians after the arrival of Indo-Aryans. Interestingly, the paper does not reject simple ANI-ASI admixture "often from tribal and traditionally lower-caste groups," while finding evidence for multiple layers of ANI ancestry  in several other populations.

My own analysis of Dodecad Project South Indian Brahmins arrived at a date of 4.1ky, and of North Indian Brahmins, a date of 2.3ky, which seems to be in good agreement with these results.

The authors also report that "we find that Georgians along with other Caucasus groups are consistent with sharing the most genetic drift with ANI". I had made a post on the differential relationship of ANI to Caucasus populations which seems to agree with this, and, of course, in various ADMIXTURE analyses, the component which I've labeled "West Asian" tends to be the major west Eurasian element in south Asia.

Here are the estimated admixture proportions/times from the paper:

Sadly, the warm and moist climate of India, and the adoption of cremation have probably destroyed any hope of studying much of its recent history with ancient DNA. On the other hand, the caste system has probably "fossilized" old socio-linguistic groups, allowing us to tell much by studying their differences and correlating them with groups outside India.

Coverage elsewhere: Gene Expression, HarappaDNA
Related podcast on BBC.

AJHG doi:10.1016/j.ajhg.2013.07.006

Genetic Evidence for Recent Population Mixture in India

Priya Moorjani et al.

Most Indian groups descend from a mixture of two genetically divergent populations: Ancestral North Indians (ANI) related to Central Asians, Middle Easterners, Caucasians, and Europeans; and Ancestral South Indians (ASI) not closely related to groups outside the subcontinent. The date of mixture is unknown but has implications for understanding Indian history. We report genome-wide data from 73 groups from the Indian subcontinent and analyze linkage disequilibrium to estimate ANI-ASI mixture dates ranging from about 1,900 to 4,200 years ago. In a subset of groups, 100% of the mixture is consistent with having occurred during this period. These results show that India experienced a demographic transformation several thousand years ago, from a region in which major population mixture was common to one in which mixture even between closely related groups became rare because of a shift to endogamy.

Link

Y chromosomes in Lingayat and Vokkaliga Dravidians from SW India

From the paper:

The virtual absence of Z283 subclades, namely Z280 and M458, and the total representation of R1a1a-derived samples by the Z93 marker in our dataset support an earlier observation that the M198 chromosome likely differentiated in the region between Eastern Europe and South Asia (Pamjav et al., 2012), and subsequently expanded in opposite directions. However, it will require additional R1a1a* samples from different populations across Eurasia to comprehensively evaluate the geographic origins, distribution and ethno-linguistic associations of the individual M198-derived lineages (Pamjav et al., 2012).

This study extends the results of Pamjav et al. 2012 which found only Z93 within R1a1 in mainland Indian populations. The authors estimate 12.8ky as the age of R-Z93 in the Lingayat, but since this uses the evolutionary mutation rate it should actually be divided by a factor of 3.6 which translates into ~1,500BC. So, it seems quite likely that R-Z93 moved from Central->South Asia during the Bronze Age, both on account of its age and the fact that it is a subset of Central Asian diversity. Haplogroup R2 with a nominal age of ~22ky in the Lingayat seems more like a Neolithic lineage.

Also of interest:

Another haplogroup that is associated with the spread of agriculture from the Fertile Crescent and Anatolia regions is J2-M172 (Cinnioğlu et al., 2004 and Semino et al., 2004). According to Sahoo et al. (2006), only J2 lineages, originating from West Asia rather than Central Asia, represent an external contribution to the Indian paternal gene pool. In particular, subclade J2a-M410 is believed to have entered through the northwestern corridor and subsequently diffused to the south and east (Sahoo et al., 2006 and Thangaraj et al., 2010). This haplogroup is present exclusively in the Lingayat (6.93%), except for one individual from Vokkaliga, suggesting gene flow from West Asia (Sahoo et al., 2006 and Thangaraj et al., 2010). Interestingly, four J2b2-M241 Lingayat males displayed a null allele at DYS458 and failed to produce the AMGY PCR amplicon while their X homolog (AMGX) amplified successfully. Comparison of Y-STR haplotypes of the affected males from the present study with those from the literature (Cadenas et al., 2006), demonstrated a high level of allele sharing, implying shared paternal lineages or a recent common ancestry for these groups of individuals.

According to the paper the Lingayat are a community that originally attracted members from across the caste system, while the Vokkaliga are involved in farming. An uneven distribution of haplogroup J2a has been previously observed, so I guess this paper adds to this evidence.

Gene Available online 7 May 2013

Indigenous and foreign Y-chromosomes characterize the Lingayat and Vokkaliga populations of Southwest India

Shilpa Chennakrishnaiah et al.

Previous studies have shown that India's vast coastal rim played an important role in the dispersal of modern humans out of Africa but the Karnataka state, which is located on the southwest coast of India, remains poorly characterized genetically. In the present study, two Dravidian populations, namely Lingayat (N = 101) and Vokkaliga (N = 102), who represent the two major communities of the Karnataka state, were examined using high-resolution analyses of Y-chromosome single nucleotide polymorphisms (Y-SNPs) and seventeen short tandem repeat (Y-STR) loci. Our results revealed that the majority of the Lingayat and Vokkaliga paternal gene pools are composed of four Y-chromosomal haplogroups (H, L, F* and R2) that are frequent in the Indian subcontinent. The high level of L1-M76 chromosomes in the Vokkaligas suggests an agricultural expansion in the region, while the predominance of R1a1a1b2-Z93 and J2a-M410 lineages in the Lingayat indicates gene flow from neighboring south Indian populations and West Asia, respectively. Lingayat (0.9981) also exhibits a relatively high haplotype diversity compared to Vokkaliga (0.9901), supporting the historical record that the Lingayat originated from multiple source populations. In addition, we detected ancient lineages such as F*-M213, H*-M69 and C*-M216 that may be indicative of genetic signatures of the earliest settlers who reached India after their migration out of Africa.

Link

Mapping Human Genetic Diversity in Asia

From the press release:

Several genome-wide studies of human genetic diversity have been conducted on European populations. Now, for the first time, these studies have been extended to 73 Southeast Asian (SEA) and East Asian (EA) populations.

In a paper titled, "Mapping Human Genetic Diversity in Asia," published online Science on 10 Dec. 2009, over 90 scientists from the Human Genome Organisation's (HUGO's) Pan-Asian SNP Consortium report that their study conducted within and between the different populations in the Asia continent showed that genetic ancestry was highly correlated with ethnic and linguistic groups.

The scientists also reported a clear increase in genetic diversity from northern to southern latitudes. Their findings also suggest that there was one major inflow of human migration into Asia arising from Southeast Asia, rather than multiple inflows from both southern and northern routes as previously proposed. This indicates that Southeast Asia was the major geographic source of East Asian and North Asian populations.

(A figure illustrating the paper shows plausible routes of pre-historical migration of Asian human populations. According to the study, the PanAsia SNP Initiative, the most recent common ancestors of Asians arrived first in India and later, some of them migrated to Thailand, and South to the lands known today as Malaysia, Indonesia, and the Philippines. The first group of settlers must have gone very far south before they settled successfully. These included the Malay Negritos , Philippine Negritos , the East Indonesians, and early settlers of the Pacific Islands. Thereafter, one or several groups of people migrated North, mixed with previous settlers there and, finally, formed various populations we now refer to as Austronesian, Austro-Asiatic, Tai-Kadai, Hmong-Mien, and Altaic. The figure is titled, "Putative Pre-Historical Migration Routes of Asian Human Populations.")

The researchers noted that the geographical and linguistic basis of genetic subgroups in Asia clarifies the need for genetic stratification when conducting genetic and pharmacogenomic studies in this continent, and that human genetic mapping of Asia has important implications for the study of genetics and disease and for research to understand migratory patterns in human history.

HUGO President Edison Liu, M.D., who is Executive Director of the Genome Institute of Singapore (GIS), said, "This study was a milestone not only in the science that emerged, but the consortium that was formed. Ten Asian countries came together in the spirit of solidarity to understand how we were related as a people, and we finished with a truly Asian scientific community. We overcame shortage of funds and diverse operational constraints through partnerships, good will, and cultural sensitivity.

"Our next goal is to expand this collaboration to all of Asia including Central Asia and the Polynesian Islands," said Dr. Liu, one of the corresponding authors of the paper. "We also aim to be more detailed in our genomic analysis and plan to include structural variations, as well as over a million single nucleotide polymorphisms in the next analysis."

While HUGO initiated and coordinated the research, Dr. Liu pointed out, "Affymetrix, led by Dr. Giulia C. Kennedy and based in the US, is our primary technology partner in this endeavour. We greatly appreciate their support."

As usual for a Science paper there are voluminous (and free) supplementary materials. The Neighbor-Joining tree shows the clear correlation between linguistic affiliation and genetic identity of individuals.


UPDATE: As to the main thesis of the paper, namely that East Asians are descended from Southeast Asians rather than Central Asians, I have to say that I am not convinced. This thesis is based on two observations: minimum sharing between East Asians and Central/South Asians and south-north reduction of genetic diversity in East Eurasians. However, the high genetic diversity in Southeast Asians can be explained if they are taken to be old hybrids of Mongoloid northerners with "Australoid"-like southerners as physical anthropology suggests, and the seeming absence of influence of present-day Central/South Asians is due to the fact that the latter are largely Caucasoids of western Eurasian origin, and, thus, do not represent any putative ancestral populations to modern Mongoloids.

Science doi:10.1126/science.1177074

Mapping Human Genetic Diversity in Asia

The HUGO Pan-Asian SNP Consortium

Abstract

Asia harbors substantial cultural and linguistic diversity, but the geographic structure of genetic variation across the continent remains enigmatic. Here we report a large-scale survey of autosomal variation from a broad geographic sample of Asian human populations. Our results show that genetic ancestry is strongly correlated with linguistic affiliations as well as geography. Most populations show relatedness within ethnic/linguistic groups, despite prevalent gene flow among populations. More than 90% of East Asian (EA) haplotypes could be found in either Southeast Asian (SEA) or Central-South Asian (CSA) populations and show clinal structure with haplotype diversity decreasing from south to north. Furthermore, 50% of EA haplotypes were found in SEA only and 5% were found in CSA only, indicating that SEA was a major geographic source of EA populations.

Link

560K SNP study reveals dual rigin of Indian populations (Reich et al. 2009)

In lieu of a prologue, Herodotus and Arrian on the two groups inhabiting ancient India:

Herodotus of Halicarnassus, Histories, Book 7:

The Indians wore cotton dresses, and carried bows of cane, and arrows also of cane with iron at the point. Such was the equipment of the Indians, and they marched under the command of Pharnazathres the son of Artabates. [...] The eastern Ethiopians- for two nations of this name served in the army- were marshalled with the Indians. They differed in nothing from the other Ethiopians, save in their language, and the character of their hair. For the eastern Ethiopians have straight hair, while they of Libya are more woolly-haired than any other people in the world.

Arrian, Anabasis, Book 8:

The appearance of the inhabitants, too, is not so far different in India and Ethiopia; the southern Indians resemble the Ethiopians a good deal, and, are black of countenance, and their hair black also, only they are not as snub-nosed or so woolly-haired as the Ethiopians; but the northern Indians are most like the Egyptians in appearance.

The paper establishes a number of different facts, that have been hinted at in previous autosomal studies, and studies based on Y chromosomes and mtDNA:

1. Modern Indians are derived from two ancestral populations. The first one, termed Ancestral North Indians (ANI) were Caucasoids, the other, Ancestral South Indians (ASI) were distinct from both Caucasoids and Mongoloids in a Eurasian context.
2. The ASI no longer exist in non-admixed form, but in various degrees of admixtures with ANI; the closest living population to the ASI are the Andaman Islanders.
3. Upper castes are higher in ANI ancestry than middle and lower castes. ANI percentages of ancestry are correlated with Western Eurasian Y chromosomes (P=0.04) and mtDNA (P=0.08).
4. Indo-European speakers are higher in ANI ancestry than Dravidian speakers.

This paper does seem to imply that Indians are a mixture of Western Eurasians and indigenous Indians. However, we should not conclude that they are a simple 2-way mix of invading Indo-Aryans and indigenous Dravidians: for example, the ANI component could be a palimpsest of different Caucasoid populations who came to the subcontinent over time. For example, we do know that South Americans are composed of Amerindians, Caucasoids, and Negroids in different proportions of admixture, but this does not mean that there was a simple mix between the three, but rather a continuous process of migration that brought (and continues to bring) people into the New World. It remains to be seen which groups participated in the diffusion of the ANI component in India.

However, the fact that ANI is correlated with caste status and language does suggest that the Indo-Aryan migration who brought Indo-European languages to India has not been totally wiped out genetically. Indo-European populations have maintained a higher degree of ancestry from the ANI component, and upper caste Indo-Europeans have maintained an even higher degree of such ancestry.

The beauty of this study is that it does not consider either a simple mixture model (like STRUCTURE does) in which populations are derived from 2 or more ancestral ones, or a simple branching model, in which populations are derived tree-like from a common root with no admixture between them. Rather, they consider both tree-like divergence of populations followed by admixture. The following figure from the paper illustrates this:
We can see that (i) the relationship between Andaman Islanders and ASI is not particularly close, although they do form a clade in relation to the other populations, (ii) the relationship between CEU and ANI is fairly close (in this context). The authors further determine (in the supplement) that CEU and ANI do form a clade separate from the non-IE speaking Adygei from the Caucasus.

What is now needed is to calculate the genetic distances between ANI and a wide assortment of Western Eurasian populations. Indeed, as these populations have undergone their own processes of admixture (e.g., Near Eastern populations with Arabs, Turks with Central Asians, Russians with Finns, Central Asian Iranians with Turks and Mongols, and so on), we cannot generally infer that the source population(s) of the ANI component are extant in non-admixed form. Nonetheless, the discovery of a strong relationship of ANI with a West Eurasian population may help us pinpoint the geographical origin of ANI outside India.

The paper does demolish some theories that have been popular in some circles:

There is no evidence of caste as simply social division of labor. This thesis is inconsistent with differential ANI admixture (and distance from Western Eurasians) across the caste hierarchy.

There is no evidence that Indo-Aryan and Dravidian speakers differ only in language. It is now clear that they are different from each other genetically as well, and this difference is not an "internal affair" of India, but is related to populations outside it. Indo-Aryan speakers differ precisely in having a larger ANI component.

There is no evidence that Indo-European languages originated in India. Let us consider what this would entail:

1. Suppose postulated ancient Indian PIE speakers had a similar genetic makeup as modern Indians (i.e., a mix of ANI and ASI). Then, the absence of the ASI component outside South Asia cannot be explained.
2. If ancient Indian PIE speakers had a purely ANI makeup, then the absence of the ASI component outside South Asia -as in (1)- can be explained. However, this would entail that sharply differentiated populations (ANI and ASI) co-existed in India without mixing for thousands of years; ANI-like PIEs spread from India with their languages; ANI and ASI admixed afterwards. To say that this scenario is not parsimonious would be charitable.
3. The only way in which PIE languages may have originated in India would be if they spread without the spread of people. However, before the advent of writing and modern means of transportation and communication, the only way to spread languages was by migration of people.

From a related Nature story:

The researchers also found that Indian populations were much more highly subdivided than European populations. But whereas European ancestry is mostly carved up by geography, Indian segregation was driven largely by caste. "There are populations that have lived in the same town and same village for thousands of years without exchanging genes," says Reich.

The paper has plentiful (and free) supplementary information.

Related posts by Gene Expression and John Hawks.

Nature 461, 489-494 doi:10.1038/nature08365

Reconstructing Indian population history

David Reich et al.

Abstract

India has been underrepresented in genome-wide surveys of human variation. We analyse 25 diverse groups in India to provide strong evidence for two ancient populations, genetically divergent, that are ancestral to most Indians today. One, the 'Ancestral North Indians' (ANI), is genetically close to Middle Easterners, Central Asians, and Europeans, whereas the other, the 'Ancestral South Indians' (ASI), is as distinct from ANI and East Asians as they are from each other. By introducing methods that can estimate ancestry without accurate ancestral populations, we show that ANI ancestry ranges from 39–71% in most Indian groups, and is higher in traditionally upper caste and Indo-European speakers. Groups with only ASI ancestry may no longer exist in mainland India. However, the indigenous Andaman Islanders are unique in being ASI-related groups without ANI ancestry. Allele frequency differences between groups in India are larger than in Europe, reflecting strong founder effects whose signatures have been maintained for thousands of years owing to endogamy. We therefore predict that there will be an excess of recessive diseases in India, which should be possible to screen and map genetically.

Link

Phylogeography of macrohaplogroup M in India

A nice little open access review paper from the Indian Journal of Genetics.

Journal of Genetics Volume 88, Number 1, April 2009

Phylogeographic distribution of mitochondrial DNA macrohaplogroup M in India

Suvendu Maji, S. Krithika and T. S. Vasulu

Abstract

Indian subcontinent harbours both the human mtDNA macrohaplogroups M and N, of which M is the most prevalent. In this study, we discuss the overall distribution of the various haplogroups and sub-haplogroups of M among the different castes and tribes to understand their diverse pattern with respect to geographical location and linguistic affiliation of the populations. An overview of about 170 studied populations, belonging to four distinct linguistic families and inhabiting different geographic zones, revealed wide diversity of about 22 major haplogroups of M. The tribal populations belonging to the same linguistic family but inhabiting different geographical regions (Dravidian and Austro–Asiatic speakers) exhibited differences in their haplogroup diversity. The northern and southern region castes showed greater diversity than the castes of other regions.

Link (pdf)

Auton et al. on Global distribution of genomic diversity

The full supplementary materials from this study are not online yet [UPDATE (May 2): You can read my comments on the suppplement here]. This seems to be based on a presentation from ASHG 2008. As I explained in that post, because Europe was settled from the east, it is expected that genomic diversity (left) would be higher in SE Europe and lower in SW Europe. However, the opposite is true. This, coupled with the observation of a higher degree of haplotype sharing between SW Europe and the Yoruba HapMap sample, suggests that genomic diversity in the Iberian peninsula has been enriched directly from Africa.

The STRUCTURE analysis is not quite clear, but clusters centered in Europe, Mexico, South Asia, East Asia, and Yoruba appear. From the figure, it appears that a little bit of "South Asian" appears in Europe, which may represent either a Gypsy element, or the more general "light blue" element which appeared in Li et al. Figure B, shows variability of Mexicans, who are mainly a European-Amerindian mix. Figure B distinguishes between Japanese and Chinese. Figure D distinguishes between Dravidian and non-Dravidian South Asians.
The POPRES sample has been previously used in a study on geography and genetic structure in Europe.

Genome Research doi:10.1101/gr.088898.108

Global distribution of genomic diversity underscores rich complex history of continental human populations

Adam Auton et al.

Abstract

Characterizing patterns of genetic variation within and among human populations is important for understanding human evolutionary history and for careful design of medical genetic studies. Here, we analyze patterns of variation across 443,434 SNPs genotyped in 3,845 individuals from four continental regions. This unique resource allows us to illuminate patterns of diversity in previously under studied populations at the genome-wide scale including Latin America, South Asia, and Southern Europe. Key insights afforded by our analysis include quantifying the degree of admixture in a large collection of individuals from Guadalajara, Mexico; identifying language and geography as key determinants of population structure within India; and elucidating a North-South gradient in haplotype diversity within Europe. We also present a novel method for identifying long-range tracts of homozygosity indicative of recent common ancestry. Application of our approach suggests great variation within and among populations in the extent of homozygosity suggesting both demographic history (such as population bottlenecks) and recent ancestry events (such as consanguinity) play an important role in patterning variation in large modern human populations.

Link

mtDNA haplogroup M2 in India

BMC Evolutionary Biology doi: 10.1186/1471-2148-8-230

The earliest settlers' antiquity and evolutionary history of Indian populations: evidence from M2 mtDNA lineage

Satish Kumar et al.

Abstract

Background

The "out of Africa" model postulating single "southern route" dispersal posits arrival of "Anatomically Modern Human" to Indian subcontinent around 66–70 thousand years before present (kyBP). However the contributions and legacy of these earliest settlers in contemporary Indian populations, owing to the complex past population dynamics and later migrations has been an issue of controversy. The high frequency of mitochondrial lineage "M2" consistent with its greater age and distribution suggests that it may represent the phylogenetic signature of earliest settlers. Accordingly, we attempted to re-evaluate the impact and contribution of earliest settlers in shaping the genetic diversity and structure of contemporary Indian populations; using our newly sequenced 72 and 4 published complete mitochondrial genomes of this lineage.

Results

The M2 lineage, harbouring two deep rooting subclades M2a and M2b encompasses approximately one tenth of the mtDNA pool of studied tribes. The phylogeographic spread and diversity indices of M2 and its subclades among the tribes of different geographic regions and linguistic phyla were investigated in detail. Further the reconstructed demographic history of M2 lineage as a surrogate of earliest settlers' component revealed that the demographic events with pronounced regional variations had played pivotal role in shaping the complex net of populations phylogenetic relationship in Indian subcontinent.

Conclusion

Our results suggest that tribes of southern and eastern region along with Dravidian and Austro-Asiatic speakers of central India are the modern representatives of earliest settlers of subcontinent. The Last Glacial Maximum aridity and post LGM population growth mechanised some sort of homogeneity and redistribution of earliest settlers' component in India. The demic diffusion of agriculture and associated technologies around 3 kyBP, which might have marginalized hunter-gatherer, is coincidental with the decline of earliest settlers' population during this period.

Link

Genetic affinities of Uttar Pradesh populations

BMC Genet. 2007 Apr 7;8(1):12 [Epub ahead of print]

Genetic affinities between endogamous and inbreeding populations of Uttar Pradesh.


Khan F, Pandey AK, Tripathi M, Talwar S, Bisen PS, Borkar M, Agrawal S.

ABSTRACT: BACKGROUND: India has experienced several waves of migration since the Middle Paleolithic. It is believed that the initial demic movement into India was from Africa along the southern coastal route, approximately 60,000-85,000 years before present (ybp). It has also been reported that there were two other major colonizations which included eastward diffusion of Neolithic farmers (Elamo Dravidians) from Middle East sometime between 10,000 and 7,000 ybp and a southern dispersal of Indo Europeans from Central Asia 3,000 ybp. Mongol entry during the thirteenth century A.D. as well as some possible minor incursions from South China 50,000 to 60,000 ybp may have also contributed to cultural, linguistic and genetic diversity in India. Therefore, the genetic affinity and relationship of Indians with other world populations and also within India are often contested. In the present study, we have attempted to offer a fresh and immaculate interpretation on the genetic relationships of different North Indian populations with other Indian and other world populations. RESULTS: We have first genotyped 20 tetra-nucleotide STR markers among 1800 north Indian samples of nine endogamous populations belonging to three different socio-cultural strata. Genetic distances (Neis DA and Reynolds Fst) were calculated among the nine studied populations, Caucasians and East Asians. This analysis was based upon the allelic profile of 20 STR markers to assess the genetic similarity and differences of the north Indian populations. North Indians showed a stronger genetic relationship with the Europeans (DA 0.0341 and Fst 0.0119) as compared to the Asians (DA 0.1694 and Fst - 0.0718). The upper caste Brahmins and Muslims were closest to Caucasians while middle caste populations were closer to Asians. Finally, three phylogenetic assessments based on two different NJ and ML phylogenetic methods and PC plot analysis were carried out using the same panel of 20 STR markers and 20 geo-ethnic populations. The three phylogenetic assessments revealed that north Indians are clustering with Caucasians. CONCLUSIONS: The genetic affinities of Indians and that of different caste groups towards Caucasians or East Asians is distributed in a cline where geographically north Indians and socially both upper caste and Muslim populations are genetically closer to the Caucasians.

Link

AAPA 2007 abstracts

The 2007 meeting of the American Association of Physical Anthropologists will be held in about a month. As in previous years, here are some interesting abstracts to be presented at the meeting (pdf).

(up to page 94)

Homo floresiensis Cranial and Mandibular Morphology
J.Y. Anderson, University of New Mexico
These results suggest the Flores material does not represent a population derived from Australomelanesians, and do not represent a non-pathological dwarfed population of Homo sapiens. These results do not completely rule out a representation of a microcephalic dwarfed population, at the same time it is suggested possible affinities to earlier hominin groups is equally parsimonious.

Do Qafzeh and Skhūl represent the ancestors of Upper Paleolithic modern humans? A dental perspective.
S.E. Bailey et al.
If these fossils represent the source of early Upper Paleolithic people, there is no need to invoke admixture with Neandertals to explain archaic dental features observed in some early Upper Paleolithic humans.

Ancient Cemetery Social Patterning Project: Ancient DNA in Tirup Cemetery.
L.E. Baker et al.

Reconstructing the settlement history of the central Andes from mitochondrial DNA analyses.
K. Batai et al.
We found that among central Andean ancient and modern population samples, haplogroup B frequencies increased through time, while haplogroup A frequencies declined. At this point, we do not yet have sufficient data to determine whether these patterns indicate different population histories between ancient coastal and modern highland populations, or a larger temporal trend in entire central Andes region

Analysis of Genetic Diversity in Ethnic Populations of Afghanistan
P. Bermudez et al.
The Middle East has the distinction of being a major crossroads of human migration. The genetic diversity of Afghanistan, however, has long remained a missing piece to this rich and complex puzzle. To explore both the diversity within Afghanistan and to understand the relative genetic contributions from various groups throughout the Eurasian continent, buccal swabs were collected from 252 unrelated Afghani men for mitochondrial DNA analysis. Each of these men hailed from
one of four major ethnic groups inhabiting the region: the Pashtun, Hazara, Tajik or
Nooristani. The Indo-Iranian speaking Pashtun represent the largest ethnic group in Afghanistan; the Tajiks have a complex genetic history that likely involves admixture between Turkic groups and smaller distinct ethnic groups within Afghanistan; the Hazara, on the other hand, are thought to represent remnants of Ghengis Khan’s army left behind as it expanded through Asia; and the Nooristani have biological links to populations in northern Pakistan and the
claim of descent from Alexander the Great’s army. All samples were analyzed for HVS1
and SNP variation. In all of these populations, Western Eurasian haplogroups (H, HV, R, J, I, U, X) were most common, with the highest frequency occurring in the Nooristanis, while the remaining East Eurasian haplogroups including D, G, and various other M types. The results of this study will be instrumental in expanding our knowledge of Afghani genetic history, in addition to broadening our understanding of population migrations throughout West and Central Asia.

Dental variation in Holocene Khoesan populations.
W. Black et al.

Are the Koh an indigenous population of the Hindu Kush? II: a dental morphology investigation.

S. Blaylock and B.E. Hemphill

Little is known about the population history of the ethnic groups in Chitral District, Pakistan, an area long been regarded as the “crossroads of Asia.” Some scholars emphasize that the Koh lifeway is the consequence of long-standing indigenous isolation. Others stress the equestrian
tradition among Koh villagers indicate they are descendants of Central Asians who emigrated across the Hindu Kush Mountains during the second millennium BC. To still others, an array of Persian linguistic inclusions indicates the Koh are more recent emigrants from the Iranian Plateau. This investigation tests these hypotheses for Koh origins through assessment of dental
morphology variations of the permanent dentition scored as 17 tooth-trait combination in accordance with the Arizona State University Dental Morphology System in a sample of 134 Kho school children from Chitral City. These data were contrasted with 17 additional samples. Comparisons are in two stages and include cluster analysis, multidimensional scaling and principal coordinates analysis. First, sex-pooled and sex-specific data compared Koh to six contemporary ethnic groups from India. Results indicate the Koh share equidistant affinities to Indo-European speaking west-Central Indian and Dravidianspeaking South Indian ethnic groups.
Second, sex-pooled data compared the Koh to 13 prehistoric samples from Neolithic to Early Iron Age sites located in the Indus Valley, Central Asia and the Iranian Plateau. Results indicate that the Koh share little affinity to prehistoric Indus Valley groups. Rather, the Koh share nearly equal affinities to prehistoric inhabitants of the Iranian Plateau and Central Asia.

A Howells grasp on prehistoric and recent Japan: A precursor to the Kennewick connection.
C. L. Brace, N. Seguchi.
Using many more samples, our results are compatible with what Howells showed for his Japanese comparisons, and,using the neighbor-joining technique, we can go on to show that Kennewick ties with the Ainu who are the descendants of the Jōmon.The Jōmon then are the probable ancestors of
the first inhabitants of the western hemisphere.

Admixture in Mexico City: implications for admixture mapping.
E. Cameron et al.
"The average proportions of Native American, European and West African admixture were estimated as 65%, 30% and 5% respectively."

"In a logistic model with higher educational status as dependent variable, the odds ratio for higher educational status associated with an increase from 0 to 1 in European admixture proportions was 9.4 (95% credible interval 3.8 – 22.6). This association of socioeconomic status with individual admixture proportion shows that genetic stratification in this population is
paralleled, and possibly maintained, by socioeconomic stratification."

Intracontinental Distribution of Haplotype Variation: Implications for Human Demographic History.
M.C. Campbell et al.
"These results suggest that diverse African populations were more subdivided with lower levels of gene flow during human history."

Social stratification in a Christian cemetery? An assessment of stress indicators and social status at Anglo-Saxon Raunds.
E.F. Craig, J.L. Buckberry
"The occurrence of statistically more individuals with both cribra orbitalia and tibial periostitis in plain graves rather than graves with stone arrangements, and LEH in plain graves rather than graves with a cover or marker, suggests that individuals buried in more elaborate graves enjoyed better levels of health and may been of higher social status than those buried in plain graves."

Variability of the Stature of the Central European Population from the Neolithic Age to Present
M. Dobisíková, S. Katina, P. Velemínský
The aim of our contribution is to characterize the changes of the stature in adult populations that have lived in Central Europe from the Neolithic period up to the present. Our sample consisted of 802 male and 704 female skeletons. The evaluation was conducted taking into account the demographic structure of the groups studied. We confronted the findings with the living
conditions of the populations known to have a significant impact on human stature, in
addition to genetic factors. We thus considered the socioeconomic status of the populations that might have influenced the quality of nutrition. We focused our attention on the socioeconomic aspect of populations of the early Middle Ages and the recent population. We compared socially higher placed part of the society with socially poorer classes (agricultural groups) (177 male, 178 female) in the early-medieval population of Great Moravia. No statistically significant
differences were found among individual social groups. To calculate the stature of last populations we used the regression equations developed by Breitiger (1937) and Bach (1965). The
calculation was based only on the length of the femur that is directly involved in body length. The impact of the secular trend was evaluated in the recent population. We compared two autopsy skeletal samples from the beginning and ends of the 20th century (107 male, 53 female). Statistically significant differences between them was found. Finally, we proposed regression equations for calculating the stature of the contemporary Czech population usable in forensic practice.

A phylogeographic analysis of haplogroup D5 and its implications for the peopling of East Asia.
M.C. Dulik
While genetic studies have focused on the Altai region of South Siberia as a possible place of origin for Native Americans, it is also possible that it played a similarly significant role in the peopling of East Asia. A Siberian connection to other East Asian populations has already been proposed based on archaeological, linguistic and classical genetic marker evidence. In this study, we examined a rare and ancient haplogroup, D5c, in an effort to elucidate early population movements in East Asia. Previous studies suggested that D5 first emerged in China and
spread northwards from there. However,given the number of D5c individuals (12) and the range of variation in D5 from the Altai region, it is conceivable that this haplogroup instead originated in South Siberia and spread from there during the initial movements of Paleolithic peoples. To est this hypothesis, we obtained complete mtDNA sequences for individuals represented by aplogroups D4 and D5 and acquired additional sequences available through GenBank and published literature. We then analyzed the entire dataset with the reduced median network approach and
phylogeographic modeling. Our results suggest that Southern Siberia did play a
critical role in the spread of the D5 haplogroup. This focus on relatively unique
mtDNA lineages specific to certain populations allowed us to better understand
the processes of ancient settlement and subsequent population movements that helped shape the current genetic landscape of East Asia.

More than meets the eye: LB1, the transforming hominin.
R.B. Eckhard et al.

LB1 is not a microcephalic.
D. Falk1 et al.

Is there biological meaning to “Hispanic” in New Mexico?
H.J.H. Edgar, C.M. Willermet

Establishing the nature of the differences between skull samples from two populations.
S.P. Evans et al.
A sample of 1188 skulls from the Romano-British site at Poundbury shows differences from the 18th century sample of 822 skulls from Spitalfields. Both sites are in the south of England, but 1400 years apart in time. The differences between the sites could be due to immigrations over time and/or to adaptation to the environment. The aim of the study was to establish the nature of the differences, in particular the relative importance of genetic and acquired traits.
Frequencies of 22 selected non-metric traits in juvenile, female and male skulls were analysed. Initial logistic regression analyses established that there was a substantial difference between the two sites and between juveniles and adults, with some sexual dimorphism. The modified mean
measure of divergence, used to calculate overall distances between the groups, showed the juvenile groups to be closer to each other than to adults from their respective sites. Across sites, males were most distant from each other. The largest distance was between Spitalfields juveniles and males. Principal coordinate analysis, followed by a jackknife stability analysis, revealed a pattern indicating that this came about through growth and adaptation. Omitting traits in turn, procrustes methods were used to identify the most influential, all of which
were acquired through ageing or lifestyle. Without these traits there was no significant
difference between the two juvenile groups and no sexual dimorphism. These results show the importance of the behavioural environment in determining morphology, and the resilience of populations to genetic change.

Peopling of the Pacific: resolving the controversy.
J.S. Friedlaender et al.
"Our survey of mitochondrial DNA, Ychromosome, and over 600 short tandem repeat polymorphisms and 200 insertiondeletions from over 40 Pacific populations indicates Polynesians have their genetic
origins to both Melanesian and Taiwanese (Southeast Asian) populations in significant degrees. In Island Melanesia, there is a small but clear ancient genetic footprint in certain Oceanic-speaking populations (i.e., linguistically related to Polynesian). The survey results underscore the extraordinary diversity of Island Melanesian populations from one language group to another, and from island to island. This is the result of the small sizes of the populations and the very long extent of modern human settlement there (over 30,000 years)."

Multivariate studies of cranial form: the impact of Howells' research on defining Homo sapiens.
J.B. Gaines et al.

Demographic simulations of the admixture between foragers and farmers in central European Neolithic.
P. Galeta, J. Bruzek.

William White Howells: A physical anthropologist in the making.
E. Giles

The relationship of Nubians with their neighbors, the Egyptians.
By, K. Godde.

The Phylogeography of Haplogroup N1a
Gokcumen O et al.
Recent studies have revealed a complex geographic distribution of haplogroup N1a. This rare and distinctive lineage is widely distributed across Eurasia and Africa, but always found at very low frequencies. However, despite its rarity, the genetic diversity within N1a has remained relatively high (h=0.9605). The reduced median network of N1a haplotypes not only reflects
this level of diversity, but also exhibits several relatively well-defined branches. The
distribution of N1a is intriguing because of revealing previously unrecognized connections between populations. What makes N1a even more interesting is the prevalence of this lineage in ancient European populations. Haak et al. (2005) found that 25% of their European Neolithic
samples belonged to N1a and dated to ~5000 BCE, whereas the frequency of this lineage in contemporary Europeans is only ~0.2%. In addition, an Iron Age skeleton from Kazakhstan had an N1a haplotype, suggesting the existence of this lineage in the Altai Republic in ~500BCE (Ricaut et al. 2004). Indeed, we found several haplogroup N1a mtDNAs in indigenous Altaians and Altaian Kazakhs. To further elucidate the phylogeography of this lineage in Central Asia, we sequenced the whole mtDNA genomes of our N1a haplotypes, and analyzed the resulting data with several quantitative methods and simulation programs to estimate their expansion times and spatial
distribution in Eurasia. Our findings suggest that there are two well-defined sublineages
within N1a, and that the dispersal of this haplogroup could be associated with the Neolithic expansion and with prehistoric interactions between Central Asian and European populations.


Understanding human races: the retreat of neutralism.
Henry Harpending
Discussion and debate about human races has been dominated for decades by neutral theory and statistics. Since this literature never posed a real question, it has never produced an answer. Lewontin's 1972 paper with its claim that a value of 1/8 of a statistic like Fst is “small” and that this means that human race differences are insignificant is a staple of our textbooks. Recently geneticists have had a closer look and pointed out that Fst of 1/8 describes differences among sets of half sibs and few claim that half sibs are insignificantly related. Anthony Edwards has shown that the significance of differences is in the correlation structure of a large number of traits, again denying the Lewontin assertion that human differences are small. Alan Templeton in 1998 claimed that human races were less differentiated that races of some other large mammals, but he compared human nuclear DNA statistics with statistics from mtDNA in the other species. An appropriate comparison shows that human are more, not less, differentiated than other large mammal species. Since neutral differences are a passive
record of demographic history they are not very significant for issues of functional biology. Newly available data sources allow us to study the natural selection of race differences instead of their drift. It appears that there is a lot of ongoing evolution in our species and the loci under strong selection on different continents only partially overlap. Human race differences may be increasing rapidly.

Acceleration of adaptive evolution in modern humans.
J. Hawks and G. Cochran
Humans vastly increased in numbers during the past 40,000 years. Recent surveys of human genomic variation have suggested a large surplus of recent positive selection, indicated by excess linkage disequilibrium and skewed SNP frequency spectra. We applied estimates of prehistoric and historic population sizes to estimate the importance of population growth in explaining the number of recent adaptive mutations. Our estimates are consistent with genomic evidence in suggesting that the rate of generation of positively selected genes has increased as much as a hundredfold during the past 40,000 years.

Do skeletal features reflect this genomic evidence of selection? Under positive
selection, rapid appearance of new variants during the terminal Pleistocene and early
Holocene would cause maximal phenotypic change during the last 2000-4000 years. We compared original and published series of Holocene cranial data from Europe, Jordan, Nubia, South Africa, and China, in addition to Late Pleistocene samples from Europe and West Asia, to test the hypothesis that the genomic acceleration in positive selection correlates with phenotypic evolution during this time period. A constellation of features in the face and cranial vault, notably including endocranial volume, changed globally during this time period and documents common patterns of selection in different regions. Holocene changes were similar in pattern and chronologically faster than those at the archaic-modern transition, which themselves were rapid compared to earlier hominid evolution. In genomic and craniometric terms, the origin of modern humans was a minor event compared to more recent evolutionary changes.

Patterns of admixture in Mexican Americans assessed from 101,150 SNPs.
M.G. Hayes et al.
"No significant differences were observed between the 10 subsets, allowing us to average the admixture estimates across the subsets: 68% European, 27% Asian (as a proxy for Native American), and 6% African."

Gender, wealth, and status in Bronze Age Central Asia: a dental pathology investigation.
B.E. Hemphill.

Sahara passage: the post-glacial recolonisation of North Africa by mitochondrial L* haplotypes.
AD Holden. P Forster.

Secular trends of the European male facial skull from the Migration Period to the present.
E. Jonke et al.
We examined secular trends in the facial skull over three Central European samples spanning more than 13 centuries. Data are 43 conventional cephalometric landmark points for samples dating from 680–830 CE, from the mid-19th Century, and from living Austrian young adult males. Methods of geometric morphometrics demonstrate shape differences across the samples, and also
differences in allometry. There is a stronginteraction between these, so that group mean differences are different for small and large individuals (equivalently, allometry is
different from period to period). The oldest sample, from the Migration Period, exhibits
allometric features that may possibly be Turkic. There are implications for the
craniofacial biologist interested in growth trends or growth predictions in ethnically
mixed populations. There are also implications for the discussion concerning the morphology of the Avars (an ethnic group of probably Central Asian origin who conquered large parts of Central Europe during the Migration Period and who interbred with other incoming groups after their conquest by Charlemagne), and also the relation of these findings to current thinking on gnathic reduction trends.

Roman Gladiators - The Osseous Evidence.
F. Kanz, K. Grossschmidt

Paternal heritage for the Indonesian peoples.
T. M. Karafet et al.

Feeding the children: Isotopic evidence for weaning practices in the ancient Greek colony of Apollonia (5th-2nd centuries BC).
C. Kwok, A. Keenleyside.

Misconceptions about the postcranial skeleton of Homo floresiensis.
S.G. Larson et al.

A comparison of mitochondrial DNA and Y chromosome DNA variation on Manus Island.
K.E. Latham et al.

Genetic affinities of Indian caste and tribal groups

A new paper in BMC Genetics examines the origins of Indian population groups. There have been other recent studies on the same topic.

BMC Genet. 2006 Aug 7;7(1):42

Genetic affinities among the lower castes and tribal groups of India: Inference from Y chromosome and mitochondrial DNA.

Thanseem I, Thangaraj K, Chaubey G, Singh VK, Bhaskar LV, Reddy MB, Reddy AG, Singh L.

ABSTRACT: BACKGROUND: India is a country with enormous social and cultural diversity due to its positioning on the crossroads of many historic and pre-historic human migrations. The hierarchical caste system in the Hindu society dominates the social structure of the Indian populations. The origin of the caste system in India is a matter of debate with many linguists and anthropologists suggesting that it began with the arrival of Indo-European speakers from Central Asia about 3500 years ago. Previous genetic studies based on Indian populations failed to achieve a consensus in this regard. We analysed the Y-chromosome and mitochondrial DNA of three tribal populations of southern India, compared the results with available data from the Indian subcontinent and tried to reconstruct the evolutionary history of Indian caste and tribal populations. RESULTS: No significant difference was observed in the mitochondrial DNA between Indian tribal and caste populations, except for the presence of a higher frequency of west Eurasian-specific haplogroups in the higher castes, mostly in the north western part of India. On the other hand, the study of the Indian Y lineages revealed distinct distribution patterns among caste and tribal populations. The paternal lineages of Indian lower castes showed significantly closer affinity to the tribal populations than to the upper castes. The frequencies of deep-rooted Y haplogroups such as M89, M52, and M95 were higher in the lower castes and tribes, compared to the upper castes. CONCLUSIONS: The present study suggests that the vast majority (>98%) of the Indian maternal gene pool, consisting of Indio-European and Dravidian speakers, is genetically more or less uniform. Invasions after the late Pleistocene settlement might have been mostly male-mediated. However, Y-SNP data provides compelling genetic evidence for a tribal origin of the lower caste populations in the subcontinent. Lower caste groups might have originated with the hierarchical divisions that arose within the tribal groups with the spread of Neolithic agriculturalists, much earlier than the arrival of Aryan speakers. The Indo-Europeans established themselves as upper castes among this already developed caste-like class structure within the tribes.

Link

Origin of the Shompen

"The Shompen are the "other Nicobaris", an enigmatic tribe living in the densely forested interior of Great Nicobar. There number has been roughly estimated at 300 in 2001. Very little is known about them. Recent unpublished genetic studies have indicated that the Shompen have different origins from the "ordinary" Nicobaris, although both groups have Mongolid ancestry. The ancestral Shompen came to Great Nicobar from Sumatra, more (maybe much more) than 10,000 years ago. The Nicobaris, on the other hand, came from the east, from mainland southeast Asia many thousands of years later. There is some genetic and linguistic evidence that the two groups mixed to a limited extent. Earlier suspected links to Negrito populations, however, have not been found. A peculiarity of the Shompen discovered in 1967 was that all of 55 individuals then screened turned out to have blood group O in the ABO system."

J Hum Genet. 2006;51(3):217-26. Epub 2006 Feb 2.

Molecular insights into the origins of the Shompen, a declining population of the Nicobar archipelago.

Trivedi R, Sitalaximi T, Banerjee J, Singh A, Sircar PK, Kashyap VK.

The Shompen, one of the most isolated and poorly understood contemporary hunter-gatherer populations, inhabit Great Nicobar Island, the southernmost island of the Nicobar archipelago. Morphological imprints in the Shompen were interpreted to favour a mixed Indo-Chinese, Malay, Negrito and Dravidian origin. Analyses of the mitochondrial, Y-chromosomal and autosomal gene pool of contemporary Shompen have revealed low diversity, illustrating a founder effect in the island population. Mitochondrial sequence analyses revealed the presence of two haplogroups of R lineage: B5a, and a newly defined clade, R12. Y-chromosomal analyses demonstrated the occurrence of a single lineage found predominantly in Austro-Asiatic speakers across Asia. With the different types of genetic markers analysed, the Shompen exhibit varying levels of genetic relatedness with the Nicobarese, and Austro-Asiatic speakers of mainland India and Southeast Asia. These genetic analyses provide evidence that the Shompen, an offshoot of the Nicobarese, are descendants of Mesolithic hunter-gatherers of Southeast Asian origin, deriving from at least two source populations.

Link

Sahoo et al. (2006) online (Indian Y chromosome variation)

The new India Y-chromosome paper that I talked about in my previous blog entry is now online at the PNAS site.

Interestingly Sanghamitra Sahoo seems to have published a paper on the same topic only two months after Sanghamitra Sengupta did.

UPDATE

It is unfortunate that this paper uses a limited number of UEP markers. Hopefully, future studies will start to seek and test more recently derived markers, which are the only ones that can really address recent events authoritatively.

Moreover, no STR markers were typed, thus further limiting any possible inferences about the time depth of the various Indian lineages.

A real problem with the study is that it performed an "admixture analysis" which considered the modern Central Asians as representative of the prehistoric ones. As it is well known, Central Asians of today have substantial Mongoloid admixture from the proto-historical and historical period and are not representative of the ancient Indo-Iranian groups of the steppe.

In any case, the observations of the authors about the distribution of haplogroups in India are broadly similar to those of the other recent study, and we have to agree that the wholesale assignment of J/R/L Y chromosomes to a recent invasion cannot really be sustained.

From the paper's conclusions:

It is not necessary, based on the current evidence, to look beyond South Asia for the origins of the paternal heritage of the majority of Indians at the time of the onset of settled agriculture. The perennial concept of people, language, and agriculture arriving to India together through the northwest corridor does not hold up to close scrutiny. Recent claims for a linkage of haplogroups J2, L, R1a, and R2 with a contemporaneous origin for the majority of the Indian castes’ paternal lineages from outside the subcontinent are rejected, although our findings do support a local origin of haplogroups F* and H. Of the others, only J2 indicates an unambiguous recent external contribution, from West Asia rather than Central Asia. The current distributions of haplogroup frequencies are, with the exception of the O lineages, predominantly driven by geographical, rather than cultural determinants. Ironically, it is in the northeast of India, among the TB groups that there is clear-cut evidence for large-scale demic diffusion traceable by genes, culture, and language, but apparently not by agriculture.

This certainly seems reasonable. J2 is largely restricted to the upper castes in India, and its young age is very suggestive of an external arrival in Neolithic and later times. It is certainly beginning to stand out as the most important exogenous genetic component in the Indian population.

The conclusion that J2 arrived in India from West and not Central Asia is not well-founded, because in the Middle East J*(xJ2) is frequent, but completely lacking in India. But, perhaps, most of Middle Eastern J*(xJ2) expanded recently, with the growth of the Semitic groups and was not present in the parental population from which Indian J2 is derived. Central Asia cannot be rejected so easily though as a source for Indian J2, because the present-day Central Asians have components (within N/C/O/Q) which were probably added by Mongoloid groups recently, and are not representative of the prehistoric populations.

The next step should be to develop informative recent markers in haplogroups J2a and R1a1 to finally establish whether some of these can be unambiguously related to particular Western Eurasian populations. This might be the decisive step to conclude whether Renfrew's hypothesis A (arrival of IE languages to India with early farmers) or hypothesis B (arrival of IE languages to India with IE-ized pastoral nomads) is the correct one.

PNAS (online early)

A prehistory of Indian Y chromosomes: Evaluating demic diffusion scenarios

Sanghamitra Sahoo et al.

Understanding the genetic origins and demographic history of Indian populations is important both for questions concerning the early settlement of Eurasia and more recent events, including the appearance of Indo-Aryan languages and settled agriculture in the subcontinent. Although there is general agreement that Indian caste and tribal populations share a common late Pleistocene maternal ancestry in India, some studies of the Y-chromosome markers have suggested a recent, substantial incursion from Central or West Eurasia. To investigate the origin of paternal lineages of Indian populations, 936 Y chromosomes, representing 32 tribal and 45 caste groups from all four major linguistic groups of India, were analyzed for 38 single-nucleotide polymorphic markers. Phylogeography of the major Y-chromosomal haplogroups in India, genetic distance, and admixture analyses all indicate that the recent external contribution to Dravidian- and Hindi-speaking caste groups has been low. The sharing of some Y-chromosomal haplogroups between Indian and Central Asian populations is most parsimoniously explained by a deep, common ancestry between the two regions, with diffusion of some Indian-specific lineages northward. The Y-chromosomal data consistently suggest a largely South Asian origin for Indian caste communities and therefore argue against any major influx, from regions north and west of India, of people associated either with the development of agriculture or the spread of the Indo-Aryan language family. The dyadic Y-chromosome composition of Tibeto-Burman speakers of India, however, can be attributed to a recent demographic process, which appears to have absorbed and overlain populations who previously spoke Austro-Asiatic languages.

Link

Differentiation of Indian Proto-Australoids

Am J Phys Anthropol. 2005 Dec 1; [Epub ahead of print]

Microsatellite diversity reveals the interplay of language and geography in shaping genetic differentiation of diverse Proto-Australoid populations of west-central India.

Gaikwad S, Vasulu TS, Kashyap VK.

Microsatellite diversity was analyzed in four Proto-Australoid tribes, including Indo-European (Marathi)-speaking Katkari, Pawara, Mahadeo-Koli, and Dravidian (Gondi)-speaking groups of Maharashtra, west-central India, to understand their genetic structure and to identify the congruence between language and gene pool. Allele frequency data at 15 short tandem repeat (STR) loci in studied tribes was compared with data of 22 Indo-European- and Dravidian-speaking caste and tribal populations using heterozygosity, allele size variance, analysis of molecular variance (AMOVA), G(ST) estimate, PC plot, and Mantel correlation test. Our results demonstrate that "Gondi" tribes comprising the Madia-Gond, a hunter-gatherer population, and the agriculturist Dheria-Gond harbor lower diversity than "Marathi" tribal groups, which are culturally and genetically distinct. Katkari, a hunter-gatherer tribe, showed greater diversity and the presence of a large number of unique alleles, genetically distinct from all others except the Pawara, supporting their old cultural links. The agriculturist Pawara tribe represents a splinter subgroup of the Bhil tribe and has experienced gene flow. The Mahadeo-Koli, an agriculturally oriented tribe, displayed significant heterozygote deficiency, attributable to the practice of high endogamy. The Proto-Australoid tribal populations were genetically differentiated from castes of similar morphology, suggesting different evolutionary mechanisms operating upon the populations. The populations showed genetic and linguistic similarity, barring a few groups with varied migratory histories. The microsatellite variation clearly demonstrates the interplay of sociocultural factors including linguistic, geographical contiguity, and microevolutionary processes in shaping the genetic diversity of populations in contemporary India. This study supports the ethno-historical relationships of Indian populations.

Link

N1a in Brahmnins

Interesting tidbit from an earlier post:

The N1a haplogroup was not observed among the native American, east Asian, Siberian, Central Asian, and western European populations. The geographic distribution of haplogroup N1a is restricted to regions neighboring the Eurasian steppe zone. Its frequency is very low, less than 1.5% (Table 6), in the populations located in the western and southwestern areas of the Eurasian steppe. Haplogroup N1a is, however, more frequent in the populations of the southeastern region of the Eurasian steppe, as in Iran (but only 12 individuals were studied) and southeastern India (Karnataka and Andhra Pradesh territories). More precisely, in India haplogroup N1a is absent from the Dravidic-speaking population and is present in only five Indo-Aryan-speaking individuals, four of whom belonged to the Havik group, an upper Brahman caste (Mountain et al. 1995).

The presence of haplogroup N1a in upper caste Hindus and not in Dravidians further strengthens the case for it being associated with the Neolithic Indo-Europeans. According to this theory, the diffusion of Neolithic people led to the Indo-Europeanization of large parts of Eurasia. The recent discovery of a high frequency of N1a in Linearbandkeramik people is also consistent with this theory, and so is its presence in prehistoric Scytho-Siberians who were Iranic speakers at the edge of the Indo-European world.

mtDNA variation in India

From the article:

The geography of India has played a decisive role in the peopling of India. Populations within India have been subjected to foreign invasions and migrations from time to time, resulting in no single apparent origin for any present day population groups and a conglomeration of different Y-chromosomal lineages (Quintana-Murci et al 2001; Saha et al 2005). The maternal gene flow in and out of India has been limited since the initial settling of Indian maternal lineages (Metspalu et al 2004). Indian mtDNA lineages belong to either Asian-specific haplogroup M or western Eurasian-specific haplogroups H, I, J, K, U, W and others that were not established anywhere (Kivisild et al 1999). The high frequency and diversity of mtDNA haplogroup M, the major contributor to the Indian maternal gene pool, has been associated with its southwest-Asian origin (Roychoudhury et al 2000, 2001; Richards et al. 2003; Rajkumar et al. 2005), whereas the presence of lineage M1 in Africa (Quintana-Murci et al 1999) and lack of L3 lineages other than M and N in India has become the most parsimonious view of the origin of haplogroup M in east Africa, which has been supported by the most recent view of single rapid coastal settlement of Asia by three major mtDNA haplogroups, M, N and R (Palanichamy et al 2004; Macaulay et al 2005; Thangaraj et al 2005; Forster and Matsumura 2005) as the founding female lineages to Indian population groups. However, the restricted presence of M as M1 and the phylogeography of M1 in Africa, predominantly in the Afro-Asiatic linguistic phylum (Metspalu et al 2004), leaves the question of the origin of haplogroup M unanswered.

J Hum Genet. [Epub ahead of print]

Human mtDNA hypervariable regions, HVR I and II, hint at deep common maternal founder and subsequent maternal gene flow in Indian population groups.


S. Sharma et al.

We have analysed the hypervariable regions (HVR I and II) of human mitochondrial DNA (mtDNA) in individuals from Uttar Pradesh (UP), Bihar (BI) and Punjab (PUNJ), belonging to the Indo-European linguistic group, and from South India (SI), that have their linguistic roots in Dravidian language. Our analysis revealed the presence of known and novel mutations in both hypervariable regions in the studied population groups. Median joining network analyses based on mtDNA showed extensive overlap in mtDNA lineages despite the extensive cultural and linguistic diversity. MDS plot analysis based on Fst distances suggested increased maternal genetic proximity for the studied population groups compared with other world populations. Mismatch distribution curves, respective neighbour joining trees and other statistical analyses showed that there were significant expansions. The study revealed an ancient common ancestry for the studied population groups, most probably through common founder female lineage(s), and also indicated that human migrations occurred (maybe across and within the Indian subcontinent) even after the initial phase of female migration to India.

Link

Anthropological complexes of European Russia, Baltic States, Belarus and Ukraine

An interesting excerpt translated into English together with a descriptive map. Some terminology of N. N. Cheboksarov regarding the Europeoid race is used in this article which might not be familiar to most people, so I list it here as a reference, text copied from an online source.

II. Europeoid (Eurasian) Great Race:

1. South European (Indo-Mediterranean) Race:

(i) South Indian (Dravidian). ------- "C"
(ii) Anterior Asian
(iii) Mediterranean-Balkan
(iv) Atlanto-Black Sea. ------- "C"
(v) East European --------"C"

2. North European (Atlanto-Baltic) Race:

(i) Atlanto-Baltic
(ii) White Sea-Baltic

"C" -------- contact or transitional group