Genetics, Vol 127, 417-428, Copyright © 1991


INVESTIGATIONS

The Genetic Structure of Admixed Populations

J. C. Long
Department of Anthropology, University of New Mexico, Albuquerque, New Mexico 87131

A method for simultaneously estimating the admixture proportions of a hybrid population and Wright's fixation index, F(ST), for that hybrid is presented. It is shown that the variance of admixture estimates can be partitioned into two components: (1) due to sample size, and (2) due to evolutionary variance (i.e., genetic drift). A chi-square test used to detect heterogeneity of admixture estimates from different alleles, or loci, can now be corrected for both sources of random errors. Hence, its value for the detection of natural selection from heterogeneous admixture estimates is improved. The estimation and testing procedures described above are independent of the dynamics of the admixture process. However, when the admixture dynamics can be specified, F(ST) can be predicted from genetic principles. Two admixture models are considered here, gene flow and intermixture. These models are of value because they lead to very different predictions regarding the accumulation of genes from the parental populations and the accumulation of variance due to genetic drift. When there is not evidence for natural selection, and it is appropriate to apply these models to data, the variance effective size (N(e)) of the hybrid population can be estimated. Applications are made to three human populations: two of these are Afro-American populations and one is a Yanomamo Indian village. Natural selection could not be detected using the chi-square test in any of these populations. However, estimates of effective population sizes do lead to a richer description of the genetic structure of these populations.


This article has been cited by other articles:


Home page
GeneticsHome page
J. Divers, L. K. Vaughan, M. A. Padilla, J. R. Fernandez, D. B. Allison, and D. T. Redden
Correcting for Measurement Error in Individual Ancestry Estimates in Structured Association Tests
Genetics, July 1, 2007; 176(3): 1823 - 1833.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
J. Wang
A Coalescent-Based Estimator of Admixture From DNA Sequences
Genetics, July 1, 2006; 173(3): 1679 - 1692.
[Abstract] [Full Text] [PDF]


Home page
Proc. Natl. Acad. Sci. USAHome page
G. Bedoya, P. Montoya, J. Garcia, I. Soto, S. Bourgeois, L. Carvajal, D. Labuda, V. Alvarez, J. Ospina, P. W. Hedrick, et al.
Admixture dynamics in Hispanics: A shift in the nuclear genetic ancestry of a South American population isolate
PNAS, May 9, 2006; 103(19): 7234 - 7239.
[Abstract] [Full Text] [PDF]


Home page
Proc. Natl. Acad. Sci. USAHome page
D. A. Merriwether, J. A. Hodgson, F. R. Friedlaender, R. Allaby, S. Cerchio, G. Koki, and J. S. Friedlaender
Ancient mitochondrial M haplogroups identified in the Southwest Pacific
PNAS, September 13, 2005; 102(37): 13034 - 13039.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
L. Excoffier, A. Estoup, and J.-M. Cornuet
Bayesian Analysis of an Admixture Model With Mutations and Arbitrarily Linked Markers
Genetics, March 1, 2005; 169(3): 1727 - 1738.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
D. Falush, M. Stephens, and J. K. Pritchard
Inference of Population Structure Using Multilocus Genotype Data: Linked Loci and Correlated Allele Frequencies
Genetics, August 1, 2003; 164(4): 1567 - 1587.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
J. Wang
Maximum-Likelihood Estimation of Admixture Proportions From Genetic Data
Genetics, June 1, 2003; 164(2): 747 - 765.
[Abstract] [Full Text] [PDF]


Home page
Proc. Natl. Acad. Sci. USAHome page
F. C. Parra, R. C. Amado, J. R. Lambertucci, J. Rocha, C. M. Antunes, and S. D. J. Pena
Color and genomic ancestry in Brazilians
PNAS, January 7, 2003; 100(1): 177 - 182.
[Abstract] [Full Text] [PDF]


Home page
GeneticsHome page
L. Chikhi, M. W. Bruford, and M. A. Beaumont
Estimation of Admixture Proportions: A Likelihood-Based Approach Using Markov Chain Monte Carlo
Genetics, July 1, 2001; 158(3): 1347 - 1362.
[Abstract] [Full Text] [PDF]