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SUMMARY:Journal Club: Y-Chromosomal Variation in Sub-Saharan Africa: Insig
 hts Into the History of Niger-Congo Groups. Mol Biol Evol 28(3): 1255-1269
  - Peter Forster
DTSTART:20110303T130000Z
DTEND:20110303T140000Z
UID:TALK29574@talks.cam.ac.uk
CONTACT:Simon Baxter
DESCRIPTION:Technological and cultural innovations as well as climate chan
 ges are thought to have influenced the diffusion of major language phyla i
 n sub-Saharan Africa. The most widespread and the richest in diversity is 
 the Niger-Congo phylum\, thought to have originated in West Africa ∼10\,
 000 years ago (ya). The expansion of Bantu languages (a family within the 
 Niger-Congo phylum) ∼5\,000 ya represents a major event in the past demo
 graphy of the continent. Many previous studies on Y chromosomal variation 
 in Africa associated the Bantu expansion with haplogroup E1b1a (and someti
 mes its sublineage E1b1a7). However\, the distribution of these two lineag
 es extends far beyond the area occupied nowadays by Bantu-speaking people\
 , raising questions on the actual genetic structure behind this expansion.
  To address these issues\, we directly genotyped 31 biallelic markers and 
 12 microsatellites on the Y chromosome in 1\,195 individuals of African an
 cestry focusing on areas that were previously poorly characterized (Botswa
 na\, Burkina Faso\, Democratic Republic of Congo\, and Zambia). With the i
 nclusion of published data\, we analyzed 2\,736 individuals from 26 groups
  representing all linguistic phyla and covering a large portion of sub-Sah
 aran Africa. Within the Niger-Congo phylum\, we ascertain for the first ti
 me differences in haplogroup composition between Bantu and non-Bantu group
 s via two markers (U174 and U175) on the background of haplogroup E1b1a (a
 nd E1b1a7)\, which were directly genotyped in our samples and for which ge
 notypes were inferred from published data using linear discriminant analys
 is on short tandem repeat (STR) haplotypes. No reduction in STR diversity 
 levels was found across the Bantu groups\, suggesting the absence of seria
 l founder effects. In addition\, the homogeneity of haplogroup composition
  and pattern of haplotype sharing between Western and Eastern Bantu groups
  suggests that their expansion throughout sub-Saharan Africa reflects a ra
 pid spread followed by backward and forward migrations. Overall\, we found
  that linguistic affiliations played a notable role in shaping sub-Saharan
  African Y chromosomal diversity\, although the impact of geography is cle
 arly discernible.
LOCATION:First Floor Seminar Room\, Department of Zoology
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