August 17, 2012

African Y chromosome news (E1b1a and R-V88)

European Journal of Human Genetics advance online publication 15 August 2012; doi: 10.1038/ejhg.2012.176

Evidence from Y-chromosome analysis for a late exclusively eastern expansion of the Bantu-speaking people

Naser Ansari Pour1, Christopher A Plaster1 and Neil Bradman1

Abstract

The expansion of the Bantu-speaking people (EBSP) during the past 3000–5000 years is an event of great importance in the history of humanity. Anthropology, archaeology, linguistics and, in recent decades, genetics have been used to elucidate some of the events and processes involved. Although it is generally accepted that the EBSP has its origin in the so-called Bantu Homeland situated in the area of the border between Nigeria and the Grassfields of Cameroon, and that it followed both western and eastern routes, much less is known about the number and dates of those expansions, if more than one. Mitochondrial, Y-chromosome and autosomal DNA analyses have been carried out in attempts to understand the demographic events that have taken place. There is an increasing evidence that the expansion was a more complex process than originally thought and that neither a single demographic event nor an early split between western and eastern groups occurred. In this study, we analysed unique event polymorphism and short tandem repeat variation in non-recombining Y-chromosome haplogroups contained within the E1b1a haplogroup, which is exclusive to individuals of recent African ancestry, in a large, geographically widely distributed, set of sub-Saharan Africans (groups=43, n=2757), all of whom, except one Nilo-Saharan-speaking group, spoke a Niger-Congo language and most a Bantu tongue. Analysis of diversity and rough estimates of times to the most recent common ancestors of haplogroups provide evidence of multiple expansions along eastern and western routes and a late, exclusively eastern route, expansion.

Link

European Journal of Human Genetics advance online publication 15 August 2012; doi: 10.1038/ejhg.2012.167

The genetic landscape of Equatorial Guinea and the origin and migration routes of the Y chromosome haplogroup R-V88

Miguel González1, Verónica Gomes1,2, Ana Maria López-Parra3, António Amorim1,4, Ángel Carracedo2, Paula Sánchez-Diz2, Eduardo Arroyo-Pardo3 and Leonor Gusmão1

Abstract

Human Y chromosomes belonging to the haplogroup R1b1-P25, although very common in Europe, are usually rare in Africa. However, recently published studies have reported high frequencies of this haplogroup in the central-western region of the African continent and proposed that this represents a ‘back-to-Africa’ migration during prehistoric times. To obtain a deeper insight into the history of these lineages, we characterised the paternal genetic background of a population in Equatorial Guinea, a Central-West African country located near the region in which the highest frequencies of the R1b1 haplogroup in Africa have been found to date. In our sample, the large majority (78.6%) of the sequences belong to subclades in haplogroup E, which are the most frequent in Bantu groups. However, the frequency of the R1b1 haplogroup in our sample (17.0%) was higher than that previously observed for the majority of the African continent. Of these R1b1 samples, nine are defined by the V88 marker, which was recently discovered in Africa. As high microsatellite variance was found inside this haplogroup in Central-West Africa and a decrease in this variance was observed towards Northeast Africa, our findings do not support the previously hypothesised movement of Chadic-speaking people from the North across the Sahara as the explanation for these R1b1 lineages in Central-West Africa. The present findings are also compatible with an origin of the V88-derived allele in the Central-West Africa, and its presence in North Africa may be better explained as the result of a migration from the south during the mid-Holocene.

Link

10 comments:

Teo. said...

The Equatorial Guinea article is apparently behind a paywall, so I won't be able to check the details, but their conclusion appears to have some serious problems.

The main ethnic group in Equatorial Guinea are the Fang, who are known to have migrated all over North-Central Africa until they settled in EG just a few centuries ago, fleeing the Fulbe. It's unsurprising that they have picked up very different lineages form different R1b areas along the way. Not only that, EG is in an Iberian colonization zone, and given Portuguese and Spanish colonial practices we might expect inter-ethnic marriages to have been widespread among colonists and traders.

So

a) The diversity of African-specific lineages in EG can be explained by the convoluted migratory history of the Fang;

b) Much of the non-African specific R1b is definitely European.

Annie Mouse said...

Hmm so R1b1c did not come down from north east Africa. The origin is said to be central West Africa (according to this paper), and in the mid Holocene which I take to be 6,000 years ago.

But it must connect up with the other R1b1s somehow. So perhaps the parent travelled down the west coast of Africa from Iberia or North West Africa.

Solís said...

A migration of Eurasian carriers of an early R1b lineage that later mutated into R-V88 in Central-West Africa would be the best explanation to suit the findings of González et al. The other would be a migration of already R-V88 carriers from northwest Africa or Iberia. All the evidence thus far points that R1b in West Africa appears 6,000-9,000 years ago, so there's no reason to believe R1b is original from Africa.

According to the second paper, haplogroup E only began to become dominant across sub-Saharan Africa ~5,000 years ago, consistent with other papers (http://mbe.oxfordjournals.org/content/26/7/1581.long).

It seems that there was an original dispersion of E across North and West Africa that coincided with the dispersion of the Afro-Asiatic languages or probably earlier (I'm not sure when E1b1a appears in West Africa or if it's even East African in origin), and then another dispersion of E across Central, South and East Africa with the dispersion of the Bantu languages. Before the Bantu expansions, sub-Saharan Africa was a very different place.

Mark D said...

"All the evidence thus far points that R1b in West Africa appears 6,000-9,000 years ago, so there's no reason to believe R1b is original from Africa." Yet, this article appears to argue otherwise, at least up to a point. Clearly, R1b arose outside Africa, but from where did it arrive?

More recently from Iberia, or 6,000 to 9,000 years ago from Northwest (or Northeast) Africa? How does the R1b in Central-West Africa compare with the R1b present today in the Mahgreb? Are there any aDNA samples from the Capsian culture or other Mahgrebian sites?

Vincent said...



Actually, it is far more likely that R-V88 originated in SW Asia BEFORE it was transferred to Central-West Africa. R-V88 is found in the Near East with more diversity (i.e. STR variance) than in Africa. Gonzalez et al. would have found this if they had assembled a R-V88 sample from the Near East.

Vincent said...

A migration of Eurasian carriers of an early R1b lineage that later mutated into R-V88 in Central-West Africa would be the best explanation to suit the findings of González et al.

Actually, it is far more likely that R-V88 originated in SW Asia BEFORE it was transferred to Central-West Africa. R-V88 is found in the Near East with more diversity (i.e. STR variance) than in Africa. Gonzalez et al. would have found this if they had assembled a R-V88 sample from the Near East.

Solís said...

Mark D, Vincent:

R-P25 and R-V88 has been found, although at low frequencies, in Morocco, Tunisia, Algeria and other parts of North Africa. But I don't know if these haplogroups are more diverse, ancient or if they are the result of recent migrations from sub-Saharan Africa.

Again, I'm not saying it should be this way. A migration from West Asia is still the best explanation overall and González et al.'s paper has some problems.

But an origin of the R-V88 subclade in West-Central Africa or a migration from northwest Africa would fit this paper as it is.

sidoroffs said...

>> Are there any aDNA samples from the Capsian culture or other Mahgrebian sites?

* There are none.


>> R-V88 is found in the Near East with more diversity (i.e. STR variance) than in Africa. Gonzalez et al. would have found this if they had assembled a R-V88 sample from the Near East.

* It seems to me they're not even aware of the study that found V88 in the Near East.

Max said...

I follow with great interest the discussion on R1b-v88 and E1b in Africa. Origin of the founders is complex. My question to the experts: Does the confusion derives from the omission of the possible proto-populations inhabiting in what is now Saharan desert? In the past, this was a green land, full of wild life, and inhabitants left their paintings. Anthropological revision of the origin of these happlogroups may suggest a surprising possibility: as Sahara dried out and Europe became warmer, these people left the area. Is it crazy as an idea? I hope one can put some light to it. Thanks.

Sean C. Wright said...

"the E1b1a haplogroup, which is exclusive to individuals of recent African ancestry,"

I don't think so. E1b1a is very old and is found among people without 'recent' African ancestry.

http://druidikal.wordpress.com/2013/10/13/misleading-information-about-y-dna-haplogroup-e1b1a/


http://druidikal.wordpress.com/2013/05/06/new-subclade-found-in-haplogroup-e/