Maternal traces of deep common ancestry and asymmetric gene flow between Pygmy hunter-gatherers and Bantu-speaking farmers.
Two groups of populations with completely different lifestyles-the Pygmy hunter-gatherers and the Bantu-speaking farmers-coexist in Central Africa. We investigated the origins of these two groups and the interactions between them, by analyzing mtDNA variation in 1,404 individuals from 20 farming populations and 9 Pygmy populations from Central Africa, with the aim of shedding light on one of the most fascinating cultural transitions in human evolution (the transition from hunting and gathering to agriculture). Our data indicate that this region was colonized gradually, with an initial L1c-rich ancestral population ultimately giving rise to current-day farmers, who display various L1c clades, and to Pygmies, in whom L1c1a is the only surviving clade. Detailed phylogenetic analysis of complete mtDNA sequences for L1c1a showed this clade to be autochthonous to Central Africa, with its most recent branches shared between farmers and Pygmies. Coalescence analyses revealed that these two groups arose through a complex evolutionary process characterized by (i) initial divergence of the ancestors of contemporary Pygmies from an ancestral Central African population no more than approximately 70,000 years ago, (ii) a period of isolation between the two groups, accounting for their phenotypic differences, (iii) long-standing asymmetric maternal gene flow from Pygmies to the ancestors of the farming populations, beginning no more than approximately 40,000 years ago and persisting until a few thousand years ago, and (iv) enrichment of the maternal gene pool of the ancestors of the farming populations by the arrival and/or subsequent demographic expansion of L0a, L2, and L3 carriers.
Quintana-Murci
Lluís
L
Human Evolutionary Genetics Unit, Centre National de la Recherche Scientifique URA3012, Institut Pasteur, 75015 Paris, France.
Quach
Hélène
H
Harmant
Christine
C
Luca
Francesca
F
Massonnet
Blandine
B
Patin
Etienne
E
Sica
Lucas
L
Mouguiama-Daouda
Patrick
P
Comas
David
D
Tzur
Shay
S
Balanovsky
Oleg
O
Kidd
Kenneth K
KK
Kidd
Judith R
JR
van der Veen
Lolke
L
Hombert
Jean-Marie
JM
Gessain
Antoine
A
Verdu
Paul
P
Froment
Alain
A
Bahuchet
Serge
S
Heyer
Evelyne
E
Dausset
Jean
J
Salas
Antonio
A
Behar
Doron M
DM
D000350:Africa, Central; D001483:Base Sequence; D044383:Black People / Q000235:genetics*; D004272:DNA, Mitochondrial / Q000145:classification / Q000235:genetics; D005260:Female; D051456:Gene Flow; D050259:Genes, Mitochondrial / Q000235:genetics*; D014644:Genetic Variation; D006238:Haploidy; D006801:Humans; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D011153:Population / Q000235:genetics*; D017422:Sequence Analysis, DNA
D004272:DNA, Mitochondrial