December 31, 2006

Convergent skin color evolution in Caucasoids and Mongoloids

MBE Advance Access published online on December 20, 2006

Genetic Evidence for the Convergent Evolution of Light Skin in Europeans and East Asians

Heather L. Norton et al.

Human skin pigmentation shows a strong positive correlation with ultraviolet radiation (UVR) intensity, suggesting that variation in skin color is, at least partially, due to adaptation via natural selection. We investigated the evolution of pigmentation variation by testing for the presence of positive directional selection in six pigmentation genes using an empirical FST approach, through an examination of global diversity patterns of these genes in the CEPH-Diversity Panel, and by exploring signatures of selection in data from the International HapMap project. Additionally, we demonstrated a role for MATP in determining normal skin pigmentation variation using admixture mapping methods. Taken together (with the results of previous admixture mapping studies), these results point to the importance of several genes in shaping the pigmentation phenotype and a complex evolutionary history involving strong selection. Polymorphisms in two genes, ASIP and OCA2, may play a shared role in shaping light and dark pigmentation across the globe while SLC24A5, MATP, and TYR have a predominant role in the evolution of light skin in Europeans but not in East Asians. These findings support a case for the recent convergent evolution of a lighter pigmentation phenotype in Europeans and East Asians.


Genetic components of Argentinean population

American Journal of Physical Anthropology (Early view)

Argentine population genetic structure: Large variance in Amerindian contribution

Michael F. Seldin et al.


Argentine population genetic structure was examined using a set of 78 ancestry informative markers (AIMs) to assess the contributions of European, Amerindian, and African ancestry in 94 individuals members of this population. Using the Bayesian clustering algorithm STRUCTURE, the mean European contribution was 78%, the Amerindian contribution was 19.4%, and the African contribution was 2.5%. Similar results were found using weighted least mean square method: European, 80.2%; Amerindian, 18.1%; and African, 1.7%. Consistent with previous studies the current results showed very few individuals (four of 94) with greater than 10% African admixture. Notably, when individual admixture was examined, the Amerindian and European admixture showed a very large variance and individual Amerindian contribution ranged from 1.5 to 84.5% in the 94 individual Argentine subjects. These results indicate that admixture must be considered when clinical epidemiology or case control genetic analyses are studied in this population. Moreover, the current study provides a set of informative SNPs that can be used to ascertain or control for this potentially hidden stratification. In addition, the large variance in admixture proportions in individual Argentine subjects shown by this study suggests that this population is appropriate for future admixture mapping studies.


December 30, 2006

New edition of YHRD database is online

From the curators of YHRD:
Hi Dienekes,

we have launched release 20 of the YHRD database, the largest update ever with 4,755 new haplotypes. See the news below and a geographical overview as an attachment.

December 28 YHRD update (Lutz Roewer, Sascha Willuweit)

The largest update since the database was started in 2000! Release 20 is out with 46,720 haplotypes in 386 populations. 44,863 haplotypes of these are completely typed for 9 and 17,824 for 11 loci. Twenty-nine populations were added today: from Ningxia in China (Han), from Qinghai in China (Salar), from Hungary including Romani speakers, from Germany (Bonn), from Sweden (Saami from Jokkmokk), from Norway (Bergen), from Libya (Tripolis), from Yemen (Sanaa), from Mexico (Chihuahua and Mexico City), from Serbia (Novi Sad), from Siberia (Stony Tunguska Evenks, Yakut speaking Evenks, Yakuts, Yukaghir, Tuva), from Western Russia (Belgorod, Kaluga, Mineralnye Vody, Nizhnii Novgorod, Orel, Pskov, Saratov, Tula, Vladimir, Volot, Yaroslavl) and from Southeastern Poland. Ten populations were updated: from Colombia (province Antioquia), from Ningxia in China (Hui), from Taiwan (Han), from Norway (Eastern, Central, Northern, Southern, Western parts and from Oslo) as well as from Russia (Novgorod). In two populations erroneous allele calls were corrected: Taraz (Kazakhstan) and Andalucia/Extremadura (Spain). We would like to thank the following colleagues for submissions, updates and corrections: Bofeng Zhu and his group (Shaanxi, P.R.China), Pamszav Horolma and her group (Budapest, Hungary), Anke Junge and her group (Bonn, Germany), Cheng-Hwai Tzeng and his group (Taipei, Taiwan), Andreas Karlsson and his group (Linkoeping, Sweden), Anibal Gaviria and his group (Medellin, Colombia), Thomas Rothaemel and his group (Hannover, Germany), Berit Myhre Dupuy and her group (Oslo, Norway), Uta Immel and her group (Halle, Germany), Hector Rangel-Villalobos and his group (Ocotlan, Mexico), Miljen Maletin and his group (Novi Sad, Serbia), Brigitte Pakendorf and her group (Leipzig, Germany), Marcin Wozniak and his group (Bydgoszcz, Poland), Grzegorz Kaczmarczyk and his group (Krakow, Poland) and Maria Jose Farfan and her group (Sevilla, Spain).

We wish you a happy new year !

Lutz Roewer, Sascha Willuweit
YHRD curators

December 29, 2006

Long Life and Good Mental Function Gene Identified

Single Gene Could Lead to Long Life, Better Mental Function
Barzilai and his colleagues examined 158 people of Ashkenazi, or Eastern European Jewish, descent who were 95 years of age or older. They chose Ashkenazi Jews since current generations stem from a relatively limited number of ancestors. This means they have a comparatively uniform genetic makeup, making it easier to identify important genetic differences.

The scientists gave these volunteers a common test of mental function, consisting of 30 questions. Correctly answering 25 of the questions meant a subject passed the test. Those centenarians who passed were two to three times more likely to have a common variant of a particular gene, called the CETP gene, than those who did not. When the researchers studied another 124 Ashkenazi Jews between 75 and 85 years of age, those subjects who passed the test of mental function were five times more likely to have this gene variant than their counterparts.

December 28, 2006

Kicking is more dangerous than fists or weapons

Feet, Not Fists, Cause More Severe Injuries, Report Says
Researchers at Cardiff University in Wales examined the medical records of nearly 25,000 people treated in a local hospital between 1999 and 2005 (related photos: the new Wales).

The researchers tallied the victims' injuries according to a five-point triage scale based on the urgency of treatment needed.

Reporting in a recent issue of the journal Injury Prevention, lead study author Jonathan Shepherd and colleagues found that while kicks were less common, such assaults caused greater damage than either punches or attacks with weapons.

Sexual practices and preferences in China

Arch Sex Behav. 2006 Dec 23; [Epub ahead of print]

Sexual Practices and Sexual Satisfaction: A Population Based Study of Chinese Urban Adults.

Parish WL, Luo Y, Stolzenberg R, Laumann EO, Farrer G, Pan S.

This study examined sexual satisfaction and its social and behavioral correlates among urbanites aged 20-64 in China, using data from a nationally representative sample of 1,194 women and 1,217 men with a spouse or other long-term sexual partner with whom they had sex during the last year. The results from structural equation models suggest a multiplex set of determinants of sexual satisfaction, including relationship characteristics, sexual knowledge and personal values, physical vitality, and environmental impediments. A large proportion of the effect of these background characteristics was mediated by frequent orgasms, varied sexual practices, and perceived partner affection. In particular, much of the effect of knowledge and beliefs was mediated through variety in sexual practices. While many of the observed patterns were shared among women and men, much of the effect of relationship characteristics was mediated through perceived partner affection for women. Men, in contrast, paid greater attention to his partner's physical attractiveness and to her extramarital sex. A sexual transition is well underway in urban China, even if more rapidly for men than for women. While knowledge and values are arguably more important in this transitional period, many antecedents of sexual well-being drawn from the literature on sexual behavior in developed Western countries are also applicable to urban China.


December 25, 2006

Handsome surgeons

According to this study, movie-surgeons are handsomer than real surgeons, who are handsomer than physicians. Famous surgeons in movies that come to mind are the Jack character in Lost and the Harrison Ford character in The Fugitive, plus many people in shows like Grey's Anatomy and ER which I haven't really watched. Any other famous surgeons in movies or TV, handsome or otherwise?

Surgeons are taller and better looking than other doctors
Phenotypic differences between male physicians, surgeons and film stars

Surgeons are taller and more handsome than physicians, finds a study in this week's Christmas issue of the BMJ.

Doctors at the University of Barcelona Hospital noticed that the tallest and most handsome male students were more likely to go for surgery, and the shortest (and perhaps not so good looking) ones were more likely to become physicians.

So they decided to test the theory that, on average, surgeons are taller and better looking than physicians.

They selected a random sample of 12 surgeons and 12 physicians from the hospital plus four external controls (well known film stars who played surgeons or physicians). All subjects were matched by age (52 +/- 7 years) and sex (all men), their height was recorded and they were asked to submit a digital picture.

Pictures of all subjects were then randomly organised and shown to an independent group of eight female observers (all in the same age group as the study subjects). Observers used the "good looking score" to classify each participant (ranging from 1, ugly to 7, very good looking).

The results show that, on average, senior male surgeons are significantly taller and better looking than senior male physicians. They also show that film stars who play doctors are significantly better looking than real surgeons and physicians.

There are several potential explanations for these findings, say the authors. For example, surgeons spend a lot of time in operating rooms, which are cleaner, cooler, and have a higher oxygen content than the average medical ward, where physicians spend most of their time. They also often wear clog-type shoes that adds 2-3 cm to their perceived height.

In contrast, physicians have a tendency to hang heavy stethoscopes around their necks, which bows their heads forward and reduces their perceived height.

Further studies are needed to assess if these findings also apply to junior male surgeons and physicians, as well as to senior and junior female staff, they add.

Happy Danes

Why are Danes the world's happiest nation?

Earlier this year, Denmark came top in a world map of happiness (the UK ranked 41st out of 178 nations). And for more than 30 years it has ranked first in European satisfaction surveys. So what makes Danes so content?

Researchers in this week's Christmas issue of the BMJ decided to find out why life satisfaction in Denmark substantially exceeds that in Sweden and Finland, the two countries most similar to Denmark.

Their hypotheses range from the unlikely (hair colour, genes, food and language) to the more plausible, such as family life, health and a prosperous economy.

However, their analysis points to two explanatory factors. Firstly, winning the 1992 European Football Championship put Danes in such a state of euphoria that the country has not been the same since. This may explain the high level of life satisfaction in Denmark after 1992, they write.

Secondly, while Danes are very satisfied, their expectations for the coming year are rather low. In contrast, Italy and Greece, which rank low on life satisfaction, rank high on expectations for the year to come, together with Swedes and Finns.

The causes of the stolid depth of Danish wellbeing are undoubtedly multifactorial, they say. The Danish football triumph of 1992 has had a lasting impact, but the satisfaction of the Danes began well before 1992, albeit at a more moderate level. The key factor that explains this, and that differentiates Danes from Swedes and Finns, seems to be that Danes have consistently low (and realistic) expectations for the year to come.

So the key to happiness may lie in the fact that if you lower your expectations enough you might feel a bit better next Christmas, they conclude.

Increase of weight in Greek schoolchildren in 20th century

Med Sci Monit. 2006 Dec 18;13(1):RA8-11 [Epub ahead of print]

The secular trend of body weight of Greek schoolchildren in the 20(th) century.

Papadimitriou A, Douros K, Fretzayas A, Nicolaidou P.

Background: Improvements in socioeconomic conditions in the 20(th) century had a dramatic impact on the growth and development of children, resulting in greater somatic growth and earlier pubertal maturation. Furthermore, in the last part of that century childhood obesity took on epidemic proportions in many countries The aim of the study was to present the secular trend of body weight of Greek schoolchildren in the 20(th) century. Material/Methods: The data were taken from growth studies the authors conducted themselves or were able to find in the Greek literature. All studies were cross-sectional and spanned the years from 1920 to 1995. The studies referred mainly to children living in Athens or other major cities of the country. Results: The data were taken from growth studies the authors conducted themselves or were able to find in the Greek literature. All studies were cross-sectional and spanned the years from 1920 to 1995. The studies referred mainly to children living in Athens or other major cities of the country. Conclusions: Improvement in the socioeconomic conditions in Greece resulted in an increase in body weight in Greek schoolchildren in the 20(th) century. However, this increase tended to stop in adolescent girls.


Haplogroups H and U and Alzheimer's

Cell Mol Neurobiol. 2006 Dec 21; [Epub ahead of print]

Do Haplogroups H and U Act to Increase the Penetrance of Alzheimer's Disease?

Fesahat F, Houshmand M, Panahi MS, Gharagozli K, Mirzajani F.

1. Alzheimer's disease (AD) is the most common form of dementia in the elderly in which interplay between genes and the environment is supposed to be involved. Mitochondrial DNA (mtDNA) has the only noncoding regions at the displacement loop (D-loop) region that contains two hypervariable segments (HVS-I and HVS-II) with high polymorphism. mtDNA has already been fully sequenced and many subsequent publications have shown polymorphic sites, haplogroups, and haplotypes. Haplogroups could have important implications to understand the association between mutability of the mitochondrial genome and the disease.2. To assess the relationship between mtDNA haplogroup and AD, we sequenced the mtDNA HVS-I in 30 AD patients and 100 control subjects. We could find that haplogroups H and U are significantly more abundant in AD patients (P = 0.016 for haplogroup H and P = 0.0003 for haplogroup U), Thus, these two haplogroups might act synergistically to increase the penetrance of AD disease.


Y chromosomes of Huichol tribe of Mexico

Leg Med (Tokyo). 2006 Jul;8(4):220-5. Epub 2006 Jun 21.

Y-linked haplotypes in Amerindian chromosomes from Mexican populations: genetic evidence to the dual origin of the Huichol tribe.

Paez-Riberos LA, Munoz-Valle JF, Figuera LE, Nuno-Arana I, Sandoval-Ramirez L, Gonzalez-Martin A, Ibarra B, Rangel-Villalobos H.

We studied six Y-linked short tandem repeats (Y-STRs) to describe the internal diversity of the Amerindian haplogroup Q-M3 in 129 males from eight Mexican populations. The low gene diversity in the Huichol tribe demonstrated the effects of genetic drift, attributable to geographic isolation and founder effect. The presence of two principal paternal lineages supported the historical and anthropometric records, which indicate that Huichols were formed by the fusion of two ancestral Mexican tribes. Moreover, genetic distances and close relationships of haplotypes between Huichols and Tarahumaras were in agreement with their linguistic affiliation. The high genetic diversity of the Purepechas and wide distribution of haplotypes along the constructed network-joining tree suggest that the present genetic composition was influenced by Purepecha dominance in western Mesoamerica. The Y-haplotypes shared between populations suggest that, among the Amerindian tribes studied herein, the paternal genetic pool of Nahuas could have contributed more importantly to the European-admixed population, the Mexican-Mestizos.


Y chromosomes of Zhuang Populations

Yi Chuan Xue Bao. 2006 Dec;33(12):1060-72.

Y-chromosome Genotyping and Genetic Structure of Zhuang Populations.

Jing C, Hui L, Zhen-Dong Q, Wen-Hong L, Wei-Xiong L, Rui-Xing Y, Li J, Shang-Ling P.

Zhuang, the largest ethnic minority population in China, is one of the descendant groups of the ancient Bai-Yue. Linguistically, Zhuang languages are grouped into northern and southern dialects. To characterize its genetic structure, 13 East Asian-specific Y-chromosome biallelic markers and 7 Y-chromosome short tandem repeat (STR) markers were used to infer the haplogroups of Zhuang populations. Our results showed that O*, O2a, and O1 are the predominant haplogroups in Zhuang. Frequency distribution and principal component analysis showed that Zhuang was closely related to groups of Bai-Yue origin and therefore was likely to be the descendant of Bai-Yue. The results of principal component analysis and hierarchical clustering analysis contradicted the linguistically derived north-south division. Interestingly, a west-east clinal trend of haplotype frequency changes was observed, which was supported by AMOVA analysis that showed that between-population variance of east-west division was larger than that of north-south division. O* network suggested that the Hongshuihe branch was the center of Zhuang. Our study suggests that there are three major components in Zhuang. The O* and O2a constituted the original component; later, O1 was brought into Zhuang, especially eastern Zhuang; and finally, northern Han population brought O3 into the Zhuang populations.


December 20, 2006

High IQ and vegetarianism

See also Meat eating men's armpits smell bad to women

BMJ. 2006 Dec 15; [Epub ahead of print]

IQ in childhood and vegetarianism in adulthood: 1970 British cohort study.

Gale CR, Deary IJ, Schoon I, Batty GD, Batty GD.

OBJECTIVE: To examine the relation between IQ in childhood and vegetarianism in adulthood. DESIGN: Prospective cohort study in which IQ was assessed by tests of mental ability at age 10 years and vegetarianism by self-report at age 30 years. SETTING: Great Britain. PARTICIPANTS: 8170 men and women aged 30 years participating in the 1970 British cohort study, a national birth cohort. MAIN OUTCOME MEASURES: Self-reported vegetarianism and type of diet followed. RESULTS: 366 (4.5%) participants said they were vegetarian, although 123 (33.6%) admitted eating fish or chicken. Vegetarians were more likely to be female, to be of higher social class (both in childhood and currently), and to have attained higher academic or vocational qualifications, although these socioeconomic advantages were not reflected in their income. Higher IQ at age 10 years was associated with an increased likelihood of being vegetarian at age 30 (odds ratio for one standard deviation increase in childhood IQ score 1.38, 95% confidence interval 1.24 to 1.53). IQ remained a statistically significant predictor of being vegetarian as an adult after adjustment for social class (both in childhood and currently), academic or vocational qualifications, and sex (1.20, 1.06 to 1.36). Exclusion of those who said they were vegetarian but ate fish or chicken had little effect on the strength of this association. CONCLUSION: Higher scores for IQ in childhood are associated with an increased likelihood of being a vegetarian as an adult.


The shape of beauty

J Cosmet Dermatol. 2006 Jun;5(2):190-4

The shape of beauty: determinants of female physical attractiveness.

Fisher ML, Voracek M.

Rarely has one research area gained as much attention as that which is observed for female physical attractiveness. The past decade has resulted in numerous, exciting developments, particularly with respect to three proposed determinants of beauty: waist to hip ratio (WHR), body mass index (BMI), and curvaceousness. The goal of our paper is to provide a highly necessary review of contemporary research on the female attractiveness, including an in-depth examination of these factors. In our review, we first discuss WHR, an index of fat deposition, which is calculated by measuring the circumference of the waist compared to the circumference of the hips. WHR is controlled by the sex hormones, and increases as women age, and hence, may influence perceptions of attractiveness. This factor has been hotly contested, as some researchers have claimed that a WHR of approximately 0.7 is universally most attractive, whereas others have found inconsistent findings, or suggest the importance of other factors, such as BMI. Body mass index (BMI), calculated by dividing the body weight (in kilograms) by height (in meters) squared, serves as a measure of body fat. Although WHR and BMI are correlated, they lead to different conclusions, and the importance of BMI as a measure of female attractiveness is debated in the literature. Similar to WHR research, BMI and its role in attractiveness is not cross-culturally consistent and is affected by the availability of resources within a given environment. It may be the case that both WHR and BMI influence female attractiveness. However, there has been little investigation of this possibility. We have explored this issue in our research, which revealed that both influence attractiveness, but in addition, we noticed that curvaceousness was also a factor. Curvaceousness is the degree of "hourglass" shape as determined, for example, by the size of the bust, relative to the circumference of the hips and waist, and the size of the buttocks. However, curvaceousness does not appear to be temporally stable as a marker of attractiveness, and it is not consistent across modes of presentation. For example, models in male-oriented magazines are more curvaceous than models in female-oriented magazines. In summary, faced with these recent findings, it is difficult to ascertain agreement among the various factors, especially when researchers investigate each determinant in isolation. We conclude that, although researchers have made many important initial steps in examining female attractiveness, there remains much to be discovered.


December 17, 2006

Gene Wars

A reader posted this article in the comments section. It covers quite a lot of material regarding the use of population genetics for political reasons. See also Indigenous Populations don't trust Genographic Project, and Genetic vs. Mythical Origins.

December 16, 2006

mtDNA haplogroups M1 and U6 originated in Eurasia

See also a related National Geographic story regarding this article.

15 December 2006:
Vol. 314. no. 5806, pp. 1767 - 1770

The mtDNA Legacy of the Levantine Early Upper Palaeolithic in Africa

Anna Olivieri et al.

Sequencing of 81 entire human mitochondrial DNAs (mtDNAs) belonging to haplogroups M1 and U6 reveals that these predominantly North African clades arose in southwestern Asia and moved together to Africa about 40,000 to 45,000 years ago. Their arrival temporally overlaps with the event(s) that led to the peopling of Europe by modern humans and was most likely the result of the same change in climate conditions that allowed humans to enter the Levant, opening the way to the colonization of both Europe and North Africa. Thus, the early Upper Palaeolithic population(s) carrying M1 and U6 did not return to Africa along the southern coastal route of the "out of Africa" exit, but from the Mediterranean area; and the North African Dabban and European Aurignacian industries derived from a common Levantine source.


December 13, 2006

Sub-populations within haplogroups R1b3 and E3a

Article not on the journal website as of this writing.

Hum Mutat. 2006 Dec 8;28(1):97 [Epub ahead of print]

Sub-populations within the major European and African derived haplogroups R1b3 and E3a are differentiated by previously phylogenetically undefined Y-SNPs.

Sims LM, Garvey D, Ballantyne J.

Single nucleotide polymorphisms on the Y chromosome (Y-SNPs) have been widely used in the study of human migration patterns and evolution. Potential forensic applications of Y-SNPs include their use in predicting the ethnogeographic origin of the donor of a crime scene sample, or exclusion of suspects of sexual assaults (the evidence of which often comprises male/female mixtures and may involve multiple perpetrators), paternity testing, and identification of non- and half-siblings. In this study, we used a population of 118 African- and 125 European-Americans to evaluate 12 previously phylogenetically undefined Y-SNPs for their ability to further differentiate individuals who belong to the major African (E3a)- and European (R1b3, I)-derived haplogroups. Ten of these markers define seven new sub-clades (equivalent to E3a7a, E3a8, E3a8a, E3a8a1, R1b3h, R1b3i, and R1b3i1 using the Y Chromosome Consortium nomenclature) within haplogroups E and R. Interestingly, during the course of this study we evaluated M222, a sub-R1b3 marker rarely used, and found that this sub-haplogroup in effect defines the Y-STR Irish Modal Haplotype (IMH). The new bi-allelic markers described here are expected to find application in human evolutionary studies and forensic genetics.


Sexual preferences in China

Am J Hum Biol. 2006 Dec 7;19(1):88-95 [Epub ahead of print]

Studies of human physique and sexual attractiveness: Sexual preferences of men and women in China.

Dixson BJ, Dixson AF, Li B, Anderson MJ.

Men and women at Northwest University (n = 631), Xi'an, China, were asked to rate the attractiveness of male or female figures manipulated to vary somatotype, waist-to-hip ratio (WHR), secondary sexual traits, and other features. In study 1, women rated the average masculine somatotype as most attractive, followed by the mesomorphic (muscular), ectomorphic (slim), and endomorphic (heavily built) somatotypes, in descending order of preference. In study 2, the amount and distribution of masculine trunk (chest and abdominal) hair were altered progressively in a series of front-posed figures. Women rated figures with no or little trunk hair as most attractive. Study 3 assessed the attractiveness of front-posed male figures which varied only in length of their nonerect penis. Numerical ratings for this trait were low, but moderate lengthening of the penis (22% or 33% above average) resulted in a significant increase in scores for attractiveness. In study 4, Chinese men rated the attractiveness of back-posed female images varying in waist-to-hip ratio (WHR from 0.5-1.0). The 0.6 WHR figure was most preferred, followed by 0.7, while figures with higher ratios (0.9 or 1.0) were significantly less attractive. Study 5 rated the attractiveness of female skin color: men expressed a marked preference for images which were lighter in color, as compared to images of average or darker skin colors. These results, the first of their kind reported for a Chinese population, support the view that sexual selection has influenced the evolution of human physique and sexual attractiveness in men and women.


Physical strength in men correlates with attractiveness

Am J Hum Biol. 2006 Dec 7;19(1):82-87 [Epub ahead of print]

Male facial appearance signals physical strength to women.

Fink B, Neave N, Seydel H.

Previous studies showed that male faces with extreme features that are likely to be associated with testosterone (T) are perceived as dominant and masculine. Women were reported to prefer masculinized male faces, as they may consider T markers to be an "honest" indication of good health. However, it is also likely that female preferences for certain male faces arise from the fact that dominant- and masculine-looking males are signaling characteristics which may be beneficial in intrasexual conflict, and thereby also indicate potential achievers of high status, an important factor in female mate selection. Although numerous studies were built on this assumption, nothing is known about the relationship between perceived facial dominance and physical strength in men. We measured hand-grip strength, as a measure of overall physical strength, in a sample of 32 male students, and recorded age, body weight, and height. Seventy-nine women rated facial images of these men for dominance, masculinity, and attractiveness. After controlling for age and body weight, hand-grip strength was found to correlate significantly positively with all three measures. The present data thus support the supposition that a male's physical strength is also signaled via facial characteristics of dominance and masculinity, which are considered attractive by women


December 10, 2006

Indigenous populations don't trust Genographic Project

DNA Gatherers Hit a Snag: The Tribes Don’t Trust Them (NY Times)

SOUTH NAKNEK, Alaska — The National Geographic Society’s multimillion-dollar research project to collect DNA from indigenous groups around the world in the hopes of reconstructing humanity’s ancient migrations has come to a standstill on its home turf in North America.
From the article:
Geographic origin stories told by DNA can clash with long-held beliefs, threatening a world view some indigenous leaders see as vital to preserving their culture.
Related to the above read also Genetic vs. Mythical Origins. More from the article:
They argue that genetic ancestry information could also jeopardize land rights and other benefits that are based on the notion that their people have lived in a place since the beginning of time.
Does anyone's land rights really depend on living in a place since the beginning of time? If that was the criterion for possessing land rights, then 99.9% of the Earth's surface wouldn't belong to its current possessors. More:
In its first 18 months, the project’s scientists have had considerable success, persuading more than 18,000 people in off-the-grid places like the east African island of Pemba and the Tibesti Mountains of Chad to donate their DNA. When the North American team arrived in southwestern Alaska, they found volunteers offering cheek swabs and family histories for all sorts of reasons.
Glenn Fredericks, president of the Georgetown tribe, was eager for proof of an ancient unity between his people and American Indians elsewhere that might create greater political power. “They practice the same stuff, the lower-48 natives, as we do,” Mr. Fredericks said. “Did we exchange people? It would be good to know.”
The first large effort to collect indigenous DNA since federal financing was withdrawn from a similar proposal amid indigenous opposition in the mid-1990s, the Genographic Project has drawn quiet applause from many geneticists for resurrecting scientific ambitions that have grown more pressing. As indigenous groups intermarry and disperse at an ever-accelerating pace, many scientists believe the chance to capture human history is fast disappearing.

“Everyone else had given up,” said Mark Stoneking, a professor at the Max Planck Institute for Evolutionary Anthropology. “If they get even a fraction of what they are trying for, it will be very useful.”

I was wondering why the Genographic project has been slow to publish their research. If they had to contend with stuff like this, it all makes sense:
In May, project officials held a stormy meeting in New York with the indigenous rights group Cultural Survival while protestors carried signs reading “National Geographic Sucks Indigenous Blood.” Shortly after, the United Nations Permanent Forum on Indigenous Issues recommended suspending the project.
It is sad that stupid politics is keeping scientists from learning about humanity's past.
But among the 10 geneticists the society has given the task of collecting 10,000 samples each by the spring of 2010, Theodore G. Schurr, the project’s North American director, is in last place. Fewer than 100 vials of DNA occupy a small plastic box in his laboratory’s large freezer at the University of Pennsylvania, where he is an assistant professor of anthropology.
The reasons offered by Native American tribes are:
But almost every federally recognized tribe in North America has declined or ignored Dr. Schurr’s invitation to take part. “What the scientists are trying to prove is that we’re the same as the Pilgrims except we came over several thousand years before,” said Maurice Foxx, chairman of the Massachusetts Commission on Indian Affairs and a member of the Mashpee Wampanoag. “Why should we give them that openly?”
Someone should explain to them that scientists don't need to prove that. It has already been firmly established, indeed long before human genetics came into the picture. The point of research like that carried out by the Genographic Project is to determine how and when migrations into the Americas (and elsewhere) happened, not if they did.

Should scientists "respect" superstition for fear of offending indigenous tribes' feelings?
Some American Indians trace their suspicions to the experience of the Havasupai Tribe, whose members gave DNA for a diabetes study that University of Arizona researchers later used to link the tribe’s ancestors to Asia. To tribe members raised to believe the Grand Canyon is humanity’s birthplace, the suggestion that their own DNA says otherwise was deeply disturbing.

Division of Labor among Neanderthals and Modern Humans

CURRENT ANTHROPOLOGY Volume 47, Number 6, December 2006

What's a Mother to Do?
The Division of Labor among Neandertals and Modern Humans in Eurasia

by Steven L. Kuhn and Mary C. Stiner

Recent hunter-gatherers display much uniformity in the division of labor along the lines of gender and age. The complementary economic roles for men and women typical of ethnographically documented hunter-gatherers did not appear in Eurasia until the beginning of the Upper Paleolithic. The rich archaeological record of Middle Paleolithic cultures in Eurasia suggests that earlier hominins pursued more narrowly focused economies, with women's activities more closely aligned with those of men with respect to schedule and ranging patterns than in recent forager systems. More broadly based economies emerged first in the early Upper Paleolithic in the eastern Mediterranean region and later in the rest of Eurasia. The behavioral changes associated with the Upper Paleolithic record signal a wider range of economic and technological roles in forager societies, and these changes may have provided the expanding populations of Homo sapiens with a demographic advantage over other hominins in Eurasia.


December 08, 2006

Cranial morphology and population history

Cranial morphology has been used to determine patterns of population history, but it is not "neutral" but is correlated with climate. For example, equatorial populations in Africa and Oceania have rather wide noses and narrow skulls compared to more northerly populations; this is not due to any close family relationship, but rather because of adaptation in similar environments.

This new paper tries to determine how different parts of cranial morphology reflect climate vs. population history.

The Anatomical Record Part A: Discoveries in Molecular, Cellular, and Evolutionary Biology, Volume 288A, Issue 12 , Pages 1225 - 1233

Human cranial anatomy and the differential preservation of population history and climate signatures

Katerina Harvati, Timothy D. Weaver


Cranial morphology is widely used to reconstruct evolutionary relationships, but its reliability in reflecting phylogeny and population history has been questioned. Some cranial regions, particularly the face and neurocranium, are believed to be influenced by the environment and prone to convergence. Others, such as the temporal bone, are thought to reflect more accurately phylogenetic relationships. Direct testing of these hypotheses was not possible until the advent of large genetic data sets. The few relevant studies in human populations have had intriguing but possibly conflicting results, probably partly due to methodological differences and to the small numbers of populations used. Here we use three-dimensional (3D) geometric morphometrics methods to test explicitly the ability of cranial shape, size, and relative position/orientation of cranial regions to track population history and climate. Morphological distances among 13 recent human populations were calculated from four 3D landmark data sets, respectively reflecting facial, neurocranial, and temporal bone shape; shape and relative position; overall cranial shape; and centroid sizes. These distances were compared to neutral genetic and climatic distances among the same, or closely matched, populations. Results indicate that neurocranial and temporal bone shape track neutral genetic distances, while facial shape reflects climate; centroid size shows a weak association with climatic variables; and relative position/orientation of cranial regions does not appear correlated with any of these factors. Because different cranial regions preserve population history and climate signatures differentially, caution is suggested when using cranial anatomy for phylogenetic reconstruction.


Armand Leroi on Neo-Eugenics

Armand Leroi has a new article on neo-eugenics. Gene Expression summarizes its content. From the article:
Will neo-eugenics spread? Probably. At least it is hard to see what will stop it if, as I claim, it becomes possible to detect all known disease-causing mutations before birth or implantation, if the cost of IVF and PGD declines, and if eugenic screens have clear economic benefits. Some readers might find it peculiar that in this discussion of neo-eugenics, I have not considered the ethical or legal implications with which this subject is generally considered to be fraught. Although I do not doubt their importance, I simply have no particular knowledge of them. Peter Medawar put it best 40 years ago: "If the termination of a pregnancy is now in question, scientific evidence might tell us that the chances of a defective birth are 100 percent, 50 percent, 25 percent, or perhaps unascertainable. The evidence is highly relevant to the decision, but the decision itself is not a scientific one, and I see no reason why scientists as such should be specially well-qualified to make it" (Medawar, 1966).
What Leroi is saying is that it will be economical to test all known disease causing mutation on the cheap. Right now it is possible to test such mutations individually, but the cost and ease of testing for all of them is too steep.

Of course, this raises important issues for parents. Chances are that random recombination will result in embryos having at least some of the genetic susceptibilities of their parents. So, while parents will be able to choose which babies they don't want, they won't be able (at least easily) to custom-order "perfect" babies, i.e., those that score negatively for all disease-causing mutations.

EMBO reports 7, 12, 1184–1187 (2006)

The future of neo-eugenics. Now that many people approve the elimination of certain genetically defective fetuses, is society closer to screening all fetuses for all known mutations?

Armand Marie Leroi


December 07, 2006

Extreme Patterns of Variance in Small Populations

Ann Hum Genet. 2006 Nov 28; [Epub ahead of print]

Extreme Patterns of Variance in Small Populations: Placing Limits on Human Y-Chromosome Diversity through Time in the Vanuatu Archipelago.

Cox M.

Small populations are dominated by unique patterns of variance, largely characterized by rapid drift of allele frequencies. Although the variance components of genetic datasets have long been recognized, most population genetic studies still treat all sampling locations equally despite differences in sampling and effective population sizes. Because excluding the effects of variance can lead to significant biases in historical reconstruction, variance components should be incorporated explicitly into population genetic analyses. The possible magnitude of variance effects in small populations is illustrated here via a case study of Y-chromosome haplogroup diversity in the Vanuatu Archipelago. Deme-based modelling is used to simulate allele frequencies through time, and conservative confidence bounds are placed on the accumulation of stochastic variance effects, including diachronic genetic drift and contemporary sampling error. When the information content of the dataset has been ascertained, demographic models with parameters falling outside the confidence bounds of the variance components can then be accepted with some statistical confidence. Here I emphasize how aspects of the demographic history of a population can be disentangled from stochastic variance effects, and I illustrate the extreme roles of genetic drift and sampling error for many small human population datasets.


Cannibalistic Neanderthals

The BBC reports:
Starvation and cannibalism were part of everyday life for a population of Neanderthals living in northern Spain 43,000 years ago, a study suggests.

Bones and teeth from the underground cave system of El Sidron in Asturias bear the hallmarks of a tough struggle for survival, researchers say.

Analysis of teeth showed signs of starvation or malnutrition in childhood and human bones have cut marks on them.

Details appear in the Proceedings of the National Academy of Sciences.

December 06, 2006

Origin of Y chromosome haplogroup N in Asia

The haplogroup N/Tat-C "controversy" is finally over.

UPDATE: Also of interest:
Interestingly, 14 N2-individuals from Turkey, data from Cinnioglu et al6 (updated in this study), belong to the Asian subcluster N2-A, suggesting that the clade N2 might have geographically expanded from Siberia westward by at least two different flows: one northwest through the Volga-Ural region, giving rise to N2-E, probably mainly via the Finno-Ugric group, and the other, N2-A, southwest together with Turkic languages.

European Journal of Human Genetics advance online publication 6 December 2006; doi: 10.1038/sj.ejhg.5201748

A counter-clockwise northern route of the Y-chromosome haplogroup N from Southeast Asia towards Europe

Siiri Rootsi1,10, Lev A Zhivotovsky2,10, Marian Baldovic caron1,3, Manfred Kayser4, Ildus A Kutuev1,5, Rita Khusainova1,5, Marina A Bermisheva1,5, Marina Gubina1,6, Sardana A Fedorova1,7, Anne-Mai Ilumäe1, Elza K Khusnutdinova5, Mikhail I Voevoda6, Ludmila P Osipova6, Mark Stoneking8, Alice A Lin9, Vladimir Ferak3, Jüri Parik1, Toomas Kivisild1, Peter A Underhill9 and Richard Villems1


A large part of Y chromosome lineages in East European and East Asian human populations belong to haplogroup (hg) NO, which is composed of two sister clades N-M231 and O-M175. The O-clade is relatively old (around 30 thousand years (ky)) and encompasses the vast majority of east and Southeast Asian male lineages, as well as significant proportion of those in Oceanian males. On the other hand, our detailed analysis of hg N suggests that its high frequency in east Europe is due to its more recent expansion westward on a counter-clock northern route from inner Asia/southern Siberia, approximately 12–14 ky ago. The widespread presence of hg N in Siberia, together with its absence in Native Americans, implies its spread happened after the founder event for the Americas. The most frequent subclade N3, arose probably in the region of present day China, and subsequently experienced serial bottlenecks in Siberia and secondary expansions in eastern Europe. Another branch, N2, forms two distinctive subclusters of STR haplotypes, Asian (N2-A) and European (N2-E), the latter now mostly distributed in Finno-Ugric and related populations. These phylogeographic patterns provide evidence consistent with male-mediated counter-clockwise late Pleistocene–Holocene migratory trajectories toward Northwestern Europe from an ancestral East Asian source of Paleolithic heritage.


December 05, 2006

Pioneering study shows richest 2 percent own half world wealth

From the EurekAlert public release:
The richest 2% of adults in the world own more than half of global household wealth according to a path-breaking study released today by the Helsinki-based World Institute for Development Economics Research of the United Nations University (UNU-WIDER).

The most comprehensive study of personal wealth ever undertaken also reports that the richest 1% of adults alone owned 40% of global assets in the year 2000, and that the richest 10% of adults accounted for 85% of the world total. In contrast, the bottom half of the world adult population owned barely 1% of global wealth.

The research finds that assets of $2,200 per adult placed a household in the top half of the world wealth distribution in the year 2000. To be among the richest 10% of adults in the world required $61,000 in assets, and more than $500,000 was needed to belong to the richest 1%, a group which — with 37 million members worldwide — is far from an exclusive club.

And from the BBC:
The richest 2% of adults in the world own more than half of all household wealth, according to a new study by a United Nations research institute.

The report, from the World Institute of Development Economics Research at the UN University, says that the poorer half of the world's population own barely 1% of global wealth.

There have of course been many studies of worldwide inequality.

But what is new about this report, the authors say, is its coverage.

It deals with all countries in the world - either actual data or estimates based on statistical analysis - and it deals with wealth, where most previous research has looked at income.

What they mean by wealth in this study is what people own, less what they owe - their debts. The assets include land, buildings, animals and financial assets.

December 01, 2006

Sexual preferences for human physique in Cameroon

Arch Sex Behav. 2006 Nov 30; [Epub ahead of print]

Human Physique and Sexual Attractiveness: Sexual Preferences of Men and Women in Bakossiland, Cameroon.

Dixson BJ, Dixson AF, Morgan B, Anderson MJ.

Men and women living in a rural community in Bakossiland, Cameroon were asked to rate the attractiveness of images of male or female figures manipulated to vary in somatotype, waist-to-hip ratio (WHR), secondary sexual traits, and other features. In Study 1, women rated mesomorphic (muscular) and average male somatotypes as most attractive, followed by ectomorphic (slim) and endomorphic (heavily built) figures. In Study 2, amount and distribution of masculine trunk (chest and abdominal) hair was altered progressively in a series of front-posed male figures. A significant preference for one of these images was found, but the most hirsute figure was not judged as most attractive. Study 3 assessed attractiveness of front-posed male figures which varied only in length of the non-erect penis. Extremes of penile size (smallest and largest of five images) were rated as significantly less attractive than three intermediate sizes. In Study 4, Bakossi men rated the attractiveness of back-posed female images varying in WHR (from 0.5-1.0). The 0.8 WHR figure was rated markedly more attractive than others. Study 5 rated the attractiveness of female skin color. Men expressed no consistent preference for either lighter or darker female figures. These results are the first of their kind reported for a Central African community and provide a useful cross-cultural perspective to published accounts on sexual selection, human morphology and attractiveness in the U.S., Europe, and elsewhere.