Whole-mtDNA Genome Sequence Analysis of Ancient African Lineages

Whole-mtDNA Genome Sequence Analysis of Ancient African Lineages

Mary Katherine Gonder*, Holly M. Mortensen*, Floyd A. Reed*, Alexandra de Sousa, and Sarah A. Tishkoff* 
 
Studies of human mitochondrial (mt) DNA genomes demonstrate that the root of the human phylogenetic tree occurs in Africa. Although 2 mtDNA lineages with an African origin (haplogroups M and N) were the progenitors of all non-African haplogroups, macrohaplogroup L (including haplogroups L0–L6) is limited to sub-Saharan Africa. Several L haplogroup lineages occur most frequently in eastern Africa (e.g., L0a, L0f, L5, and L3g), but some are specific to certain ethnic groups, such as haplogroup lineages L0d and L0k that previously have been found nearly exclusively among southern African “click” speakers. Few studies have included multiple mtDNA genome samples belonging to haplogroups that occur in eastern and southern Africa but are rare or absent elsewhere. This lack of sampling in eastern Africa makes it difficult to infer relationships among mtDNA haplogroups or to examine events that occurred early in human history. We sequenced 62 complete mtDNA genomes of ethnically diverse Tanzanians, southern African Khoisan speakers, and Bakola Pygmies and compared them with a global pool of 226 mtDNA genomes. From these, we infer phylogenetic relationships amongst mtDNA haplogroups and estimate the time to most recent common ancestor (TMRCA) for haplogroup lineages. These data suggest that Tanzanians have high genetic diversity and possess ancient mtDNA haplogroups, some of which are either rare (L0d and L5) or absent (L0f) in other regions of Africa. We propose that a large and diverse human population has persisted in eastern Africa and that eastern Africa may have been an ancient source of dispersion of modern humans both within and outside of Africa.

Firstly, I feel obliged to point out that M and N both have a Eurasian origin. Okay, so the origin of M was up for a debate a while ago, but I’ve never seen N down as African in origin. Where did that come from? This is contradicted in the full text:

For example, mtDNAs of Tanzanians belonging to haplogroup M1 cluster with peoples from Oceania, whereas Tanzanian mtDNAs belonging to haplogroup N1 and J cluster with peoples of Middle Eastern and Eurasian origin. However, the presence of haplogroups N1 and J in Tanzania suggest “back” migration from the Middle East or Eurasia into eastern Africa, which has been inferred from previous studies of other populations in eastern Africa (Kivisild et al. 2004).

I’m trying to figure out if there was a migration South from east Africa that might explain the Hofmeyr skull. Anyone with any thoughts on this, let me know.

 

3 responses to “Whole-mtDNA Genome Sequence Analysis of Ancient African Lineages

  1. Hmmm… The supplementary material only mentions haplogroup M1 in the samples, what seems to mean also back-migration from West Asia (I don’t know why they say they cluster with Oceanians).

    I’m trying to figure out if there was a migration South from east Africa that might explain the Hofmeyr skull. Anyone with any thoughts on this, let me know.

    Petragia et al, 2007 associates the Jawalpuram technology of Middle Paleolithic India to Southern African (and not East African) MSA. Not sure how to interpretate this but it does seem to suggest that the border between Eastern and Southern Africa was not something strict in the Middle Paelolithic (obviously people could not migrate from Southern Africa to South Asia directly by boat then).

  2. I am sorry but … WTF??? I knew Africans were geneticallly varied but this is confusing. Some think “interbreeding” with “Pygmies” and “Bushmen” are the reason for it. Hopefully in the near future we have all this sorted out. Mathilda, you have offically convinced me there is some truth to the multiregional origin of Humans after all. But my guess is more hybridization with other “species” (Neanderhal, Homo Erectus … etc.) than that we have completely seperate origins. That would be to big of a coincidence. I some theorists say that Neanderthal genes may be expressing in some Autistic children. I do not really agree with that explanation for it b/c the syntoms vary from child to child, Autism is fairly new and 29% of Autistic children express genius traits. What do you think about that?

  3. “it does seem to suggest that the border between Eastern and Southern Africa was not something strict in the Middle Paelolithic”.

    Or any other time. There seems always to have been more contact between these two regions than between either and West Africa going back to Australopithecus times. Although a relatively recent expansion of agricultural groups from WA into both regions has occurred.

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