posted
This is one of the most confusing African haplogroups, it seems to be all over the place. Could anyone tell me where it originated, whether it has regional sub-clades, and its age. Thanks.
Posts: 424 | Registered: May 2011
| IP: Logged |
posted
According to Salas et al. (2002) the jury is still out on origin point of this African clade; it could be western African, or just as likely, it could be eastern African.
-------------------- The Complete Picture of the Past tells Us what Not to Repeat Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
| IP: Logged |
posted
^Edit: The Explorer beat me to it.... In addition though, they do surmise that it likely first became prevalent in North Central Africa some 20,000 years ago, from where it spread both east and west.
It is difficult to trace the origin of L2a with any confidence. The deepest part of L2a, represented by clusters α1-α3, is most common in East Africa. However, the diversity and TMRCA are similar in East (61,250 [SE 13,500] years) and West (54,100 [SE 17,087] years) Africa. The diversity accumulated separately in East and West Africa, estimated from the main shared founder types (and disregarding the possibility of subsequent gene flow), is again similar in the two regions, at ~14,000 years (14,100 years [SE 5,100], and 13,800 years [SE 4,700], respectively), suggesting a separation shortly after the Last Glacial Maximum.
Perhaps, more recent studies have determined the origin point with more precision(?).
-------------------- The Complete Picture of the Past tells Us what Not to Repeat Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
| IP: Logged |
In addition though, they do surmise that it likely first became prevalent in North Central Africa some 20,000 years ago, from where it spread both east and west.
The central African origin deal was an extrapolation, having determined that:
An easterly origin for L2a also faces the following difficulties: that the other subclades of L2 (L2b, L2c, and L2d) have a clear western distribution, and that L2d diverges earlier in the mtDNA phylogeny than L2a (Torroni et al. Torroni et al., 2001). A possible solution would be an origin for L2a somewhere **between east and west**, Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
| IP: Logged |
posted
I looked up more recent studies and found that Behar et al. 2008 put the age of L2a at 46,033.
L2a has two main branches L2a2 at 30,159 and L2a1 at 27,778.
L2a2 seems to be Central-Eastern African, mainly found in the Sudan, Chad and in Pygmies in the Congo.
L2a1 has a more complex distribution.
L2a1a (19,842)- Central-Eastern African distribution (Chad, Egypt, Kenya). L2a1b (7,143) - seems to be Bantu specific (Mozambique, South Africa). L2a1c (9,524) - Sahel distribution (Burkina, Chad, Ethiopia). L2a1d (10,318)- Northeastern African distribution (Egypt, Ethiopia). L2a1e (15,080) poor African sample data, unknown location. L2a1f (13,492) - possibly Western African in origin, but also found in South Africa (could be Bantu). L2a1h (14,286) - Central-Eastern African distribution. (Kenya) L2a1i (15,873) - Western African distribution. (G. Bissau) L2a1j (6,349) - Northern African distribution (Morocco).
posted
I'm not sure what you mean by the younger age suggested by Salas et al. (2002). Their estimated ages respectively for western African and eastern African L2a clades are greater than the Behar et al. age you cited.
As for a central African origin, this was just suggested as a possibility, given the distinct geographical structuring between western African and eastern African L2a clades. To be certain, one would have to find older clades in central Africa, between eastern and western Africa.
-------------------- The Complete Picture of the Past tells Us what Not to Repeat Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
| IP: Logged |
quote:Originally posted by The Explorer: I'm not sure what you mean by the younger age suggested by Salas et al. (2002). Their estimated ages respectively for western African and eastern African L2a clades are greater than the Behar et al. age you cited.
I misread Sundjata's post, my bad.
quote:Originally posted by The Explorer: As for a central African origin, this was just suggested as a possibility, given the distinct geographical structuring between western African and eastern African L2a clades. To be certain, one would have to find older clades in central Africa, between eastern and western Africa.
L2a2 is the oldest known branch so far, and seems to be mainly found in Nilotic and Pygmy peoples of Middle Africa.
Are there any known recent L2a* samples?
Posts: 424 | Registered: May 2011
| IP: Logged |
posted
I did not accuse you of misreading Sundjata's post, but it seems to me that you overlooked a direct quote from Salas et al. themselves, as I cited.
You are putting too much emphasis on L2a2. Have you read the second quote I also cited?
Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
| IP: Logged |
posted
I don't recall to what extent L2a may be found in Egypt on top of my head. It is Salas et al. (2002) who is telling Manu what you claim I'm telling him/her. And L2d doesn't diverge from L2a. As for the origin somewhere between east and west Africa, that was just offered as a possibility, nothing concrete, as no actual molecular proof was offered for it. I was hoping *both* quotes I had posted would be taken into careful consideration. Fact is, from the reports of Salas et al., the origin of L2a in western Africa, and to a lesser degree in eastern Africa, is pretty much a considerable probability, based on actual nucleotide information.
-------------------- The Complete Picture of the Past tells Us what Not to Repeat Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
| IP: Logged |
quote:Originally posted by The Explorer: You are putting too much emphasis on L2a2. Have you read the second quote I also cited?
Well, the most ancient branch of L2a still IS L2a2, which is confined to Middle Africa, rather than the West or East.
I did read the second quote, but I don't see how it would hinder the Middle African origin hypothesis for L2a. It would for L2 in general, not so much for L2a.
Posts: 424 | Registered: May 2011
| IP: Logged |
posted
I'm aware what this "thread is about". You seem to have a problem how things fit in molecular genetics. You just don't look at L2a in a vacuum without referencing the distribution pattern of its sibling clades. Take a cue from the authors, in their consideration of other clades within the L2 family, which makes sense, since L2a distribution alone had proved, at that point, to be somewhat inconclusive. Thus additional information had to be sought elsewhere too, i.e. in the L2 family. You are misguided about some presumed intention to "hinder the Middle African" origin. It was simply pointed out that no actual proof was offered for the "possibility". It was simply tossed out there, so it seemed, because the authors were scratching their heads about the western African distribution of L2a and that of eastern Africa. Things getting any clearer?
-------------------- The Complete Picture of the Past tells Us what Not to Repeat Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
| IP: Logged |
posted
On what molecular grounds are either of you basing your claims about the "most diverse" L clades?
Ps: Having L2a* isn't necessarily going to suggest that the area carrying it is the likely origin point. It could simply be a rare L2a clade whose position within the L2 is waiting to be determined. It happens all the time in molecular genetics.
Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
| IP: Logged |
quote:Originally posted by KING: If L0 is the most diverse then I stand corrected.
I was also looking at your post of the Branches of L2a and thought maybe it was the most Diverse.
Peace
Just because something is widespread, does not mean it is genetically very diverse.
HG N is found all over the globe but its genetic diversity is very low compared to let's say L4 or any other random African maternal HG.
Posts: 424 | Registered: May 2011
| IP: Logged |
I was basing it on how L2a was found in all across Africa.
What Manu posted seemed to show the clade is linked to North, South, East and West Africa. So I figured it was the most diverse. I see now I was wrong but really is there really a clear cut Mtdna African Lineage that is the most diverse?
Peace
Posts: 9651 | From: Reace and Love City. | Registered: Oct 2005
| IP: Logged |
posted
Unlike the Y-DNA, it is relatively harder to put mtDNA phylogeny together, because it is by far more diverse comparatively, and this isn't made easier, with new additions to the network. That being said, L3 appears to be the most diverse, since it has more basal branches than any other L type.
-------------------- The Complete Picture of the Past tells Us what Not to Repeat Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
| IP: Logged |
quote:Originally posted by The Explorer: Unlike the Y-DNA, it is relatively harder to put mtDNA phylogeny together, because it is by far more diverse comparatively, and this isn't made easier, with new additions to the network.
Isn't that due to the fact that the y-chromosome usually isn't fully sequenced (only 'hot spot' regions are sequenced), while the mitochondrion usually is fully sequenced because of its small size (only ~16K base pairs). I could be wrong though.
Posts: 424 | Registered: May 2011
| IP: Logged |
posted
Nope. It has to do with the fact that mtDNA network simply has more branches, because our oldest common recent mtDNA ancestor is by far older than the male counterpart -- hence, more diversity over a more extended period of time.
Posts: 7516 | From: Somewhere on Earth | Registered: Jan 2008
| IP: Logged |
posted
^ Which is why I can't help but notice the Euronuts try to write off many L3 derived subclades especially M1 and N1 as "Eurasian".
Posts: 26236 | From: Atlanta, Georgia, USA | Registered: Feb 2005
| IP: Logged |
posted
Thank you for this. I am L2a1a (L2a1a2), and I didn't see this particular spreadsheet study.
quote:Originally posted by Manu: I looked up more recent studies and found that Behar et al. 2008 put the age of L2a at 46,033.
L2a has two main branches L2a2 at 30,159 and L2a1 at 27,778.
L2a2 seems to be Central-Eastern African, mainly found in the Sudan, Chad and in Pygmies in the Congo.
L2a1 has a more complex distribution.
L2a1a (19,842)- Central-Eastern African distribution (Chad, Egypt, Kenya). L2a1b (7,143) - seems to be Bantu specific (Mozambique, South Africa). L2a1c (9,524) - Sahel distribution (Burkina, Chad, Ethiopia). L2a1d (10,318)- Northeastern African distribution (Egypt, Ethiopia). L2a1e (15,080) poor African sample data, unknown location. L2a1f (13,492) - possibly Western African in origin, but also found in South Africa (could be Bantu). L2a1h (14,286) - Central-Eastern African distribution. (Kenya) L2a1i (15,873) - Western African distribution. (G. Bissau) L2a1j (6,349) - Northern African distribution (Morocco).
UBBFriend: Email this page to someone!
Printer-friendly view of this topic