A variety of estimators have been developed to use genetic marker information in inferring the admixture proportions (parental contributions) of a hybrid population. The majority of these estimators used allele frequency data, ignored molecular information that is available in markers such as microsatellites and DNA sequences, and assumed that mutations are absent since the admixture event. As ...

Hispanics in the U.S. Southwest have genetic ancestry from Europeans and from American Indians, two groups with markedly different breast cancer incidence rates. Genetic admixture may therefore bias estimates of associations between candidate cancer susceptibility genes and breast cancer in Hispanics. We estimated genetic admixture using 15 ancestry-informative markers for 1,239 Hispanics and 2...

Sex-biased admixture has been observed in a wide variety of admixed populations. Genetic variation in sex chromosomes and functions of quantities computed from sex chromosomes and autosomes have often been examined to infer patterns of sex-biased admixture, typically using statistical approaches that do not mechanistically model the complexity of a sex-specific history of admixture. Here, expan...

Gene flow between genetically distinct populations creates linkage disequilibrium (admixture linkage disequilibrium [ALD]) among all loci (linked and unlinked) that have different allele frequencies in the founding populations. We have explored the distribution of ALD by using computer simulation of two extreme models of admixture: the hybrid-isolation (HI) model, in which admixture occurs in a...

BACKGROUND Amerindian admixture is an important parameter to consider in epidemiological studies in American countries, to make a proper selection of cases and controls. AIM To compare Amerindian admixture estimates obtained using ABO*A and ABO*O blood group alleles and ancestral identity markers (AIMs) in the mixed Chilean population. SUBJECTS AND METHODS Amerindian admixture rates were de...

Estimating admixture histories is crucial for understanding the genetic diversity we see in present-day populations. Existing allele frequency or phylogeny-based methods are excellent for inferring the existence of admixture or its proportions, but have less power for estimating admixture times. Recently introduced approaches for estimating these times use spatial information from admixed chrom...

We introduce here a Bayesian analysis of a classical admixture model in which all parameters are simultaneously estimated. Our approach follows the approximate Bayesian computation (ABC) framework, relying on massive simulations and a rejection-regression algorithm. Although computationally intensive, this approach can easily deal with complex mutation models and partially linked loci, and it c...

The genetic structure of Costa Rica's population is complex, both by region and by individual, due to the admixture process that started during the 15th century and historical events thereafter. Previous studies have been done mostly on Amerindian populations and the Central Valley inhabitants using various microsatellites and mitochondrial DNA markers. Here, we study for the first time a rando...

A population formed by genetic admixture of two or more source populations may exhibit considerable linkage disequilibrium between genetic loci. In the presence of recombination, this linkage disequilibrium declines with time, a fact that is often ignored when considering haplotypes of closely linked systems [e.g., Gm serum group (gamma globulins), HLA, and, more recently, restriction fragment ...