Joined: 30 Mar 2005 {Posts: 1082 } Location: New Jersey
Posted: Fri 04 Nov 2005 15:11 Post subject: L, M, and U mtDNA in Iberia (was "a few interesting points")
Upon reviewing the study Mitochondrial DNA Affinities at the Atlantic Fringe of Europe (PDF accessible in the index we created), I found the following quote of interest:
Quote:
An important gene flow from Africa was detected in the Atlantic Iberia. Specific sub-Saharan lineages appeared mainly restricted to southern Portugal, and could be attributed to historic Black slave trade in the area and to a probable Saharan Neolothic influence. In fact, U6 haplotypes of specific North African origin have only been detected in the Iberian peninsula northwards from central Portugal. Based on this peculiar distribution and the high diversity [pi] value in this area compared to North Africa, we reject the proposal that only historic events such as the Moslem occupation are the main cause of this gene flow, and instead propose a pre-Neolothic origin for it.
Of interest also is that they consider M1 to be sub-Saharan.
The above study also, in one of the charts, groups M / N / L3 as one group, and I believe the reason for this is that perhaps the methods they used weren't sensitive enough to distinguish between sub-Saharan L3* and those that branched off of it (M & N). I think this is also what occurred in the Pereira study, when they mentioned that some of the L3*s may not be of recent sub-Saharan origin. They did say that the L3* was a "default group," so perhaps they couldn't distinguish between L3* and M or N as well. What led me to believe this? The quote from the following study (which I have added to the index under a new heading called "General European":
There is in the Near East a moderate frequency of clusters originating in Africa (even when Egypt and Nubiawhere the frequency of lineages of African origin is obviously higherare excluded from the Near Eastern sample): 1% L1, 1% L2, and <3% African L3* (distinguished from the Eurasian haplogroups M and N, at nucleotide positions 10400 and 10873, respectively [Quintana-Murci et al. 1999]). The cluster M1, usually found in eastern Africa (Passarino et al. 1998; Quintana-Murci et al. 1999), also occurs at <1%. Thus, sub-Saharan African input in the Near East amounts to 5%, rather less than our estimates of gene flow from Europe. There are also <1% northern-African U6 mtDNAs.
Note how they also consider M1 to be sub-Saharan, since it's most often found in eastern Africa.
Posted: Fri 04 Nov 2005 15:47 Post subject: Re: Frank...a few interesting points
Quote:
...U6 haplotypes of specific North African origin have only been detected in the Iberian peninsula northwards from central Portugal. Based on this peculiar distribution and the high diversity [pi] value in this area compared to North Africa, we reject the proposal that only historic events such as the Moslem occupation are the main cause of this gene flow, and instead propose a pre-Neolothic origin for it.
Well, that would explain the north-to-south Berber cline that we were talking about earlier. It may have nothing to do with the Almoravids and may be a remnant of the repopulation of Europe after the LGM. It is an interesting hypothesis. Come to think of it, the only real molecular (as opposed to historical) evidence we have that the Ls in Iberia are from the slave trade, rather than from the LGM repopulation, is that the L cline is south-to-north.
William wrote:
Of interest also is that they consider M1 to be sub-Saharan.
When was this study? You may be right, that they did not well-enough distinguish L from M1, which is found in Africa and the Middle East. Alternatively, they may feel that M1 was already in the diaspora band before it left Africa circa 75kya. The present consensus is that M1 back-flowed later from Asia to Africa, but it could go either way.
By the way, a really good overall survey of the current consensus on the paleolithic and early neolithic lineages/migrations, especially regarding M1, is Stephen Oppenheimer, The Real Eve: Modern Man's Journey Out of Africa (New York: Carroll & Graf, 2003). I recommend it highly.
Joined: 30 Mar 2005 {Posts: 1082 } Location: New Jersey
Posted: Fri 04 Nov 2005 16:04 Post subject:
Frank wrote:
Come to think of it, the only real molecular (as opposed to historical) evidence we have that the Ls in Iberia are from the slave trade, rather than from the LGM repopulation, is that the L cline is south-to-north.
Do we know when the L's first arose? Or are they ancient?
Frank wrote:
When was this study? You may be right, that they did not well-enough distinguish L from M1, which is found in Africa and the Middle East. Alternatively, they may feel that M1 was already in the diaspora band before it left Africa circa 75kya. The present consensus is that M1 back-flowed later from Asia to Africa, but it could go either way.
The study is from 2000. Pereira (where some L3*s were assumed to possibly be of non-recent sub-Saharan origin) was also from 2000. Perhaps Pereira, et al., should have said something like, "The L3*/N/M cluster, some of which have non-African origin, has been found. Presently we are unable to distinguish defnitely sub-Saharan L3* from non-sub-Saharan N and M."
I think this lays to rest any assumptions that some L3*s are not of recent sub-Saharan origin. All L3*s appear to be definitely sub-Saharan, as we suspected all along.
Frank wrote:
By the way, a really good overall survey of the current consensus on the paleolithic and early neolithic lineages/migrations, especially regarding M1, is Stephen Oppenheimer, The Real Eve: Modern Man's Journey Out of Africa (New York: Carroll & Graf, 2003). I recommend it highly.
'
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