RT Journal Article
SR Electronic
T1 Refining the Y chromosome phylogeny with southern African sequences
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 034983
DO 10.1101/034983
A1 Chiara Barbieri
A1 Alexander Hübner
A1 Enrico Macholdt
A1 Shengyu Ni
A1 Sebastian Lippold
A1 Roland Schröder
A1 Sununguko Wata Mpoloka
A1 Josephine Purps
A1 Lutz Roewer
A1 Mark Stoneking
A1 Brigitte Pakendorf
YR 2015
UL http://biorxiv.org/content/early/2015/12/20/034983.abstract
AB The recent availability of large-scale sequence data for the human Y chromosome has revolutionized analyses of and insights gained from this non-recombining, paternally inherited chromosome. However, the studies to date focus on Eurasian variation, and hence the diversity of early-diverging branches found in Africa has not been adequately documented. Here we analyze over 900 kb of Y chromosome sequence obtained from 547 individuals from southern African Khoisan and Bantuspeaking populations, identifying 232 new sequences from basal haplogroups A and B. We find new branches within haplogroups A2 and A3b1 and suggest that the prehistory of haplogroup B2a is more complex than previously suspected; this haplogroup is likely to have existed in Khoisan groups before the arrival of Bantu-speakers, who brought additional B2a lineages to southern Africa. Furthermore, we estimate older dates than obtained previously for both the A2-T node within the human Y chromosome phylogeny and for some individual haplogroups. Finally, there is pronounced variation in branch length between major haplogroups; haplogroups associated with Bantu-speakers have significantly longer branches. This likely reflects a combination of biases in the SNP calling process and demographic factors, such as an older average paternal age (hence a higher mutation rate), a higher effective population size, and/or a stronger effect of population expansion for Bantu-speakers than for Khoisan groups.