Inferring human population sizes, divergence times and rates of gene flow from mitochondrial, X and Y chromosome resequencing data.
We estimate parameters of a general isolation-with-migration model using resequence data from mitochondrial DNA (mtDNA), the Y chromosome, and two loci on the X chromosome in samples of 25-50 individuals from each of 10 human populations. Application of a coalescent-based Markov chain Monte Carlo technique allows simultaneous inference of divergence times, rates of gene flow, as well as changes in effective population size. Results from comparisons between sub-Saharan African and Eurasian populations estimate that 1500 individuals founded the ancestral Eurasian population approximately 40 thousand years ago (KYA). Furthermore, these small Eurasian founding populations appear to have grown much more dramatically than either African or Oceanian populations. Analyses of sub-Saharan African populations provide little evidence for a history of population bottlenecks and suggest that they began diverging from one another upward of 50 KYA. We surmise that ancestral African populations had already been geographically structured prior to the founding of ancestral Eurasian populations. African populations are shown to experience low levels of mitochondrial DNA gene flow, but high levels of Y chromosome gene flow. In particular, Y chromosome gene flow appears to be asymmetric, i.e., from the Bantu-speaking population into other African populations. Conversely, mitochondrial gene flow is more extensive between non-African populations, but appears to be absent between European and Asian populations.
Garrigan
Daniel
D
Department of Organismic and Evolutionary Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
Kingan
Sarah B
SB
Pilkington
Maya M
MM
Wilder
Jason A
JA
Cox
Murray P
MP
Soodyall
Himla
H
Strassmann
Beverly
B
Destro-Bisol
Giovanni
G
de Knijff
Peter
P
Novelletto
Andrea
A
Friedlaender
Jonathan
J
Hammer
Michael F
MF
D001483:Base Sequence; D041321:Chromosomes, Human, X; D041322:Chromosomes, Human, Y; D004272:DNA, Mitochondrial; D051456:Gene Flow; D005828:Genetics, Population; D006801:Humans; D008390:Markov Chains; D011156:Population Density; D011157:Population Dynamics; D044469:Racial Groups / Q000235:genetics
D004272:DNA, Mitochondrial