posted
The Complex and Diversified Mitochondrial Gene Pool of Berber Populations
C. Coudray1 , A. Olivieri2, A. Achilli2,3, M. Pala2, M. Melhaoui4, M. Cherkaoui5, F. El-Chennawi6, M. Kossmann7, A. Torroni2 and J. M. Dugoujon1
Summary The mitochondrial DNA variation of 295 Berber-speakers from Morocco (Asni, Bouhria and Figuig) and the Egyptian oasis of Siwa was evaluated by sequencing a portion of the control region (including HVS-I and part of HVS-II) and surveying haplogroup-specific coding region markers. Our findings show that the Berber mitochondrial pool is characterized by an overall high frequency of Western Eurasian haplogroups, a somehow lower frequency of sub-Saharan L lineages, and a significant (but differential) presence of North African haplogroups U6 and M1, thus occupying an intermediate position between European and sub-Saharan populations in PCA analysis. A clear and significant genetic differentiation between the Berbers from Maghreb and Egyptian Berbers was also observed. The first are related to European populations as shown by haplogroup H1 and V frequencies, whereas the latter share more affinities with East African and Nile Valley populations as indicated by the high frequency of M1 and the presence of L0a1, L3i, L4*, and L4b2 lineages. Moreover, haplogroup U6 was not observed in Siwa. We conclude that the origins and maternal diversity of Berber populations are old and complex, and these communities bear genetic characteristics resulting from various events of gene flow with surrounding and migrating populations.
Haplogroup frequencies (number of subjects) by population Asni Bouhria Figuig Siwa
The genetic proximity observed between the Berbers and southern Europeans reveals that these groups shared a common ancestor. Two hypotheses are discussed: one would date these common origins in the Upper Paleolithic with the expansion of anatomically modern humans, from the Near East to both shores of the Mediterranean Sea; the other supports the Near Eastern origin, but would rather date it from the Neolithic, around 10,000 years ago (Ammerman & Cavalli-Sforza 1973; Barbujani et al. 1994; Myles et al. 2005; Rando et al. 1998). Common polymorphisms (i.e. those defining H and V lineages) between Berbers and south Europeans also could have been introduced or supported by genetic flows through the Straits of Gibraltar. For example, genetic exchanges could have taken place during prehistory, while European populations retreated from ice sheets and expanded from refuge, around 15,000 years ago (as evidenced by the H and U5b mitochondrial lineages). Alternatively, these exchanges could have occurred during history, with the invasion and the occupation during nearly seven centuries (from the 8th to the 15th century) of the Iberian Peninsula by Almoravide then Almohade Muslim Berber troops. The differentiation observed between North Africans and sub-Saharan populations shows, first, that settlement of these areas was achieved by different migration waves and, then, that a genetic diversity was already observable in Africa since very old times. However, the Berber genetic heritage consists of a relatively high frequency of L lineages from various parts of Africa (i.e. L0a, L3i, L4, and L5 clades are from East Africa, L1b, L2b, and L3b are from West Africa, and L3e originated in the Sudan). It poses a question about the Sahara desert role in population movements and exchanges. It should be specified that the Sahara was not always a desert, because it also underwent enormous variation between wet and dry, offering green spaces favorable for human occupation and animal domestication (Aumassip et al. 1994; Said & Faure 1990). Thus, this is plausible that exchanges between African prehistoric populations took place; exchanges during which markers typical of sub-Saharan groups would have been introduced into the Berber gene pool. Contacts between North Africa and great sub Saharan empires (such as those of Ghana, of Mali, or the Songhai Empire) are also reported by history during trans-Saharan trade of gold, salt and slaves. The second analysis we conducted aimed to measure the relationship between the Berber communities on their whole geographical habitat. Although the Berber populations have the same overall mitochondrial genetic composition, the distribution of some markers is not the same along the Berber-speaker habitats. Our results highlighted a clear genetic differentiation between Berbers from the Maghreb and Egyptian Berbers. The first seems to be more related to European populations as shown by haplogroup H1 and V frequencies, whereas the latter share more affinities with East African and Nile Valley populations as indicated by the high frequency of M1 and the presence of L0a1, L3i, L4∗, and L4b2 lineages. Moreover, haplogroup U6 was not observed in Siwa. Probably, such a maternal diversity between North African Berbers would have been the result of a conjunction of several geographical, prehistoric, and historic factors which guided contacts (and thus exchanges) between local populations and migrating groups. First, in addition to the geographical distance, which certainly increases the genetic distance, the geographical location of Berber populations is very peculiar: the Berbers from the Maghreb are at the end of a long migration route, whereas Berbers from Siwa are rather in a crossroads between the Middle East, East Africa, sub-Saharan areas and the North African corridor. Therefore, meetings and exchanges between local and migrating populations were not identical in North West and North East Africa. In addition, prehistory and history of the populations from Maghreb are different from those of the Egyptian group. For the Siwa oasis, there is very little information on which exact prehistoric period was the starting point of Berber culture. However we know that throughout history, the oasis was crossed by successive human groups, like pilgrims traveling to Mecca, Mediterranean tradesmen, or Sahelian slave merchants. Siwa was also repopulated by Libyan Berber-speakers driven from their land by Arab conquerors. Lastly, it experienced a period of decline and has faced, between the ninth and twelfth centuries, a drastic demographic reduction of its population (Fakhry 1973). The current gene pool of the Siwa people would therefore be the result of these various genetic exchanges which occurred in the past. Overall, it is clear that neither the Strait of Gibraltar nor the Sahara desert appears to have forced the movements and exchanges between South Europeans, North Africans, and sub-Saharans. This interaction took place since prehistory in a human and genetic framework already diversified, and the maternal ancestors of the Berbers were able to exchange some markers with surrounding populations with different cultures and genetic pools. Influences from the Middle East and East Africa are marked in Siwa, while southwestern European influences are observed in the Maghreb. Although the origin of these Eurasian and sub Saharan lineages in the mitochondrial pool of Berbers is still questionable (whether due to common ancestry or past and/or current gene flow), certainly they were not diluted by the many historical invasions and migrations, leaving a clear maternal footprint in the contemporary populations. We conclude that the origins and diversity of Berber populations are old and complex, and these communities bear genetic characteristics resulting from various events of gene flow with surrounding and migrating populations.
Posts: 2007 | From: Washington State | Registered: Oct 2006
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posted
But the issue that is never addressed is what is Berber and when historically can we identify a population as Berber. Calling someone in North Africa Berber 10,000 years ago is about as useful as calling someone from the same time frame French. Neither presents any understanding of the physical biological characteristics of the populations of the time, nor does it help understand what population and biological characteristics were predominant. Berber, like French is a language and therefore has nothing to do with biological characteristics, as many people with different biological characteristics speak the language. While genetic lineages can give you an idea who was where in prehistory, you still need physical remains to get a more accurate picture of relationships. Relying on genetics will not tell you anything about when other populations arrived into the North African gene pool. Only looking at physical remains from various time depths can give you decent understanding of this.
Posts: 8895 | Registered: May 2005
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posted
^Well, original Berber speakers came from the Eastern Sahara, and these populations also have a predominantly Neolithic origin for their Y chromosome lineages.
The NW African Y chromosomes are predominantly African in origin, while their maternal lineages are predominantly non African (Eurasian).
quote:Originally posted by Evergreen: The Complex and Diversified Mitochondrial Gene Pool of Berber Populations
Alternatively, these exchanges could have occurred during history, with the invasion and the occupation during nearly seven centuries (from the 8th to the 15th century) of the Iberian Peninsula by Almoravide then Almohade Muslim Berber troops.
Which is were this above alternative theory is more plausible and the maternal gene flow most likely did occur in historic times.
Most likely during the Moorish/Muslim era. Where Muslims practiced polygamy and would of taken many wives.
quote:Originally posted by The Explorer: "Trafficking of women from the other side of the Mediterranean sea as slaves surely must have left its own mark. This coupled with a tradition of polygamy [especially amongst those sections of north African populations which were Muslim-converts] would have facilitated households with sizeable headcount of offspring per a single male 'owner'. Then there were also sudden waves of migration to the north African coast during the fall of direct northwest African rule in the Iberian peninsula; no doubt families who reached the north African coast had left some genetic imprint therein. And of course, genetic drift has its own role to play in all this. All that aside, a look at samplings so far undertaken in coastal northwest Africa suggests that these have generally relied on sampling small, scattered populations [see Cherni et al. 2005], giving fragmented or incomplete picture of northwest African maternal gene pool structure."
The caveat here is that, if Imazighen populations had found some "white European" groups upon arriving in the northwest African coast, then it certainly doesn't appear to have been one of a large population, with a sizeable European male demography. Contemporary Imazighen speakers of the North African coast have very little to essentially neglegable European male contribution in their gene pool.
Posts: 6572 | From: N.Y.C....Capital of the World | Registered: Jun 2008
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posted
Interesting study. Basically it confirms what Keita and others say about this group, that is, its genetic history is old and complex but overall they are an indigenous African group and not a foundationally admixed population as some retards in here once thought.
Posts: 4165 | From: jamaica | Registered: May 2008
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quote: The genetic proximity observed between the Berbers and southern Europeans reveals that these groups shared a common ancestor. Two hypotheses are discussed: one would date these common origins in the Upper Paleolithic with the expansion of anatomically modern humans, from the Near East to both shores of the Mediterranean Sea
Ultimately, this common ancestry may trace back to the Middle Upper Paleolithic from the "Near East", if one is referring to haplogroups H and V for instance; in particular, that date would correspond to Hgs H's and V's ancestor HV*; much of European H and V clades are of late Upper Paleolithic extraction.
quote: the other supports the Near Eastern origin, but would rather date it from the Neolithic, around 10,000 years ago (Ammerman & Cavalli-Sforza 1973; Barbujani et al. 1994; Myles et al. 2005; Rando et al. 1998). Common polymorphisms (i.e. those defining H and V lineages) between Berbers and south Europeans also could have been introduced or supported by genetic flows through the Straits of Gibraltar. For example, genetic exchanges could have taken place during prehistory, while European populations retreated from ice sheets and expanded from refuge, around 15,000 years ago (as evidenced by the H and U5b mitochondrial lineages).
Each of the scenarios mentioned here gloss over paternal uniparental lineages. Tamazight language phylum, and certainly the predominant patrilineal uniparental lineages are of the autochthonous African E-M78* markers, with the typical pan-Imazighen marker being the E-M81 subclade. The Imazighen would not have been in the Maghreb 15,000 years ago according to these markers, which more closely correlate with the Tamazight language phylum, than the mosaic and geographically structured Imazighen maternal gene pools. This is not say that markers like say, M1 and U6 for example, do not show some correspondences in this regard as well, but not to the same effect as the said patrilineal markers. Heck, even sampling in eastern Africa, which the said paternal markers suggest is the ultimate homeland of the proto-Imazighen ancestry, have not produced dates going as far as 15,000 years ago.
quote: Alternatively, these exchanges could have occurred during history, with the invasion and the occupation during nearly seven centuries (from the 8th to the 15th century) of the Iberian Peninsula by Almoravide then Almohade Muslim Berber troops.
This has certainly taken place; the question is, how much impact would this have had on the pre-existing the Maghrebian-Imazighen gene pool. Historic genetic exchanges have certainly been considerable, especially with North Africans taking into slavery, mainly involving European females.
quote: However, the Berber genetic heritage consists of a relatively high frequency of L lineages from various parts of Africa (i.e. L0a, L3i, L4, and L5 clades are from East Africa, L1b, L2b, and L3b are from West Africa, and L3e originated in the Sudan). It poses a question about the Sahara desert role in population movements and exchanges. It should be specified that the Sahara was not always a desert, because it also underwent enormous variation between wet and dry, offering green spaces favorable for human occupation and animal domestication (Aumassip et al. 1994; Said & Faure 1990). Thus, this is plausible that exchanges between African prehistoric populations took place; exchanges during which markers typical of sub-Saharan groups would have been introduced into the Berber gene pool.
As if to say, that the aboriginal Imazighen maternal gene pool was drawn from elsewhere other than sub-Saharan Africa, LOL. Boy, these folks are quite something!
posted
Again, I would say that only relying on genetics alone will not solve some of the issues revealed here. A better approach would be to find more physical remains, both for possible DNA extraction, but also for cranial analysis. In the time frames prior to 10,000 BC many of the remains found have been distinctly African. Therefore, the idea that foreign migrations had a substantial impact on the population of the time is not valid. Similar finds in Southern Libya, Algeria and so on also have a similar affinity to Africans. Therefore, it would seem that much of the "mixing" taking place in North Africa is from the last 5000 years or so with the last 2000 being the most important and having the biggest impact.
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quote:Moreover, haplogroup U6 was not observed in Siwa.
So much for the claim that M1 must be of non African origin, because it is always associated with U6, which [presumably] has a non African ancestor.
Posts: 15202 | Registered: Jun 2004
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Again, I would say that only relying on genetics alone will not solve some of the issues revealed here. A better approach would be to find more physical remains, both for possible DNA extraction, but also for cranial analysis.
Not sure about the specific context in which this is placed [pending clarification], but as far the Imazighen ("Berbers"), the subject of this topic, are concerned, it is not necessary to inspect physical remains for DNA extraction, since they are a living and breathing group.
quote: In the time frames prior to 10,000 BC many of the remains found have been distinctly African.
Agreed.
quote: Therefore, the idea that foreign migrations had a substantial impact on the population of the time is not valid. Similar finds in Southern Libya, Algeria and so on also have a similar affinity to Africans. Therefore, it would seem that much of the "mixing" taking place in North Africa is from the last 5000 years or so with the last 2000 being the most important and having the biggest impact.
Reasonable, based on thus far skeletal data collected, of the Maghrebian Upper Paleolithic, and what is known about contemporary Imazighen "characteristic" markers and language phylum for instance.
Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
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quote: Therefore, the idea that foreign migrations had a substantial impact on the population of the time is not valid. Similar finds in Southern Libya, Algeria and so on also have a similar affinity to Africans. Therefore, it would seem that much of the "mixing" taking place in North Africa is from the last 5000 years or so with the last 2000 being the most important and having the biggest impact.
Doug, since we already know physically, these populations don't match up with ancients in said areas, and genetically the disconnect has also been proven; albeit skeletal evidence being important, so is a genetic continuation.
Add to the fact; that of NW African gene pool being non African influenced heavily maternally, but not so much paternally.
Posts: 6572 | From: N.Y.C....Capital of the World | Registered: Jun 2008
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yes because they show that the intermediate genetic status of supra saharan populations are due primarily to hybridisation. Posts: 4165 | From: jamaica | Registered: May 2008
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quote:Moreover, haplogroup U6 was not observed in Siwa.
So much for the claim that M1 must be of non African origin, because it is always associated with U6, which [presumably] has a non African ancestor.
Good note taking.
I'd like to add that, and as I noted time and again, attempts to find the "expansion companions" in Upper Paleolithic markers like R1*-M173 in Africa had proven to be futile.
Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
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quote:Originally posted by The Explorer: [QB] [QUOTE]Tamazight language phylum, and certainly the predominant patrilineal uniparental lineages are of the autochthonous African E-M78* markers, with the typical pan-Imazighen marker being the E-M81 subclade. [/QB
Evergreen Writes:
Yes, and what is of interest is that E-M81 has a relatively recent derivation from E-M35. Of interest is the relatively high frequency of E-M35 among the Borgu of the Darfur.
Hassan et al 2008:
E-M35 ~ 40% of y-chromosome variation among Borgu
E-M35 ~ 29% of y-chromosome variation among Oromo
The implication being that the Borgu could be part of the ancestral group that spread across the eastern sahara and later derived into E-M81 in the mid-holocene central sahara.
Posts: 2007 | From: Washington State | Registered: Oct 2006
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posted
^ I too noticed that in the study. Have you see any supplemental information on that Hassan study? I dont think they tested for for M81? From memory we DO know that M81 is found in Sudan but a low frequencies. Do any studies state which populations such markers are found in?
Posts: 2463 | From: New Jersey USA | Registered: Dec 2007
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