June 29, 2011

Chad basin mtDNA

In a recent discussion a reader mentioned this paper that somehow I have missed:


The paper has more data but I'd say that the essence of it is in figures 1 and 2:

Fig. 1 Map of the Lake Chad Basin showing frequencies of the main African hgs in the different ethnic groups analyzed.

What I most clearly notice in this map is that L2 is dominant North of Lake Chad, while L3 is hegemonic elsewhere in the basin.

Figure 2 (not displayed because it needs high resolution for clear contemplation) is the phylogeny and commonality of the specific lineages under the wide categories shown above. Most common lineages are:
  • L0a (almost all the L0 displayed above is this sublineage). Excepting historically slave-trader nations (Arabs, Kanuri, Kanembu) it is most common south of the Lake, in North Cameroon.
  • L1b is most common among the Fulani (20-26%) being very rare in other ethnicities, except the Fali and the Kanembu.
  • L1c (usually associated with Pygmies but not exclusively) is found most commonly among the Hide (15%).
  • L2a makes up most of the L2 above, being quite common among all ethnicities (but more in the North, as mentioned for L2 overall, reaching its highest figure among Chad Arabs: 33%).
  • L2b is most common among the Mafa (11%) and Fulani (8%).
  • L2c is most common among the Tcheboua Fulani specifically (10%)
  • L3b is most common among the Fulani (28-30%) but also among many other ethnicities.
  • L3d is frequent among several groups but rare among others without any pattern I can discern. The highest frequency is that of Chad Arabs (19%).
  • L3h is quite frequent (>20%) among the peoples that live at the very shores of the lake (but the Northern ones), being most common among the Kotoko (29%).
  • L3e reaches high frequencies among diverse peoples, with a peak among the Fali (38%).
  • M1 is most common among the fishermen Buduma (10%) and also the Shuwa Arabs (13%).
  • U only reaches noticeable frequencies among the Borgor Fulani (8% U(xU6)) and Shuwa Arabs (5% U(xU6), 3% U6).
  • R0 is quite common among Chad Arabs (18.5%, all R0(xHV), surely R0a). There is some HV(xH) and H scatter but at very low frequencies.

    5 comments:

    1. It is a bit hard to discern from the paper itself the linguistic associations of the various ethnic groups. The Fulani speak a Niger-Congo language, the Arab identified groups presumably speak Arabic. But, it is hard to tell which speak Chadic languages, which speak Nilo-Saharan languages and which, if any, speak Berber languages.

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    2. Cannot help you with that. I added Wikipedia links for the peoples I could find some, others remain unknown to me too.

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    3. The study said something about one of the U6 samples belonging to the Canary Islands modal haplotype.

      I looked at population figures of the provinces sorrounding Lake Chad, and it seems about 7 or 8 million people live to the east, south, and west of the Lake, but maybe just 300,000 on the north side. The lake is at the border where the Sahel changes into the Sahara.

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    4. "What I most clearly notice in this map is that L2 is dominant North of Lake Chad, while L3 is hegemonic elsewhere in the basin".

      And an interesting trace of L4 in the northwest. I wouold have thought it as an eastern haplogroup.

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    5. Under 5% in all cases. Not sure what to do with such small apportions other than attest it does exist.

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