Ancestral inference. I. The problem and the method.

E A Thompson; C Cannings; M H Skolnick

doi:10.1111/j.1469-1809.1978.tb00934.x

Home/Archive/PubMed

PubMed · 686688

Ancestral inference. I. The problem and the method.

E A Thompson·C Cannings·M H Skolnick

View original source ↗Export metadata ↓

Abstract

A method for inferring the ancestral genotypes for the founders of a population is developed. This method uses the algorithms for the computation of probabilities on pedigrees of arbitrary complexity, developed by Cannings et al. (1978) and implemented by Thompson (1977b). When characteristics are simply determined by underlying genotypes the inference problem is simplified, and larger and more complex pedigrees may therefore be analysed. The problem of estimating the allele frequencies to be used in computing prior genotype probabilities for those founders on whom a likelihood function is not required is discussed. The same method allows us to compute extinction probabilities for any combination of original founder genes; these probabilities are interesting parameters of pedigree structure, which, since they relate to the actual genes present in a population, help to provide a clearer understanding of observed distributions of autosomal traits.

Explore related subjects

Gene Frequency Genetics, Population Genotype Humans Marriage Models, Biological Pedigree Statistics as Topic Journal Article

Keep this discovery

Explore connections, maps & timelines

BibTeX RIS

E A Thompson, C Cannings, M H Skolnick. 1978. Ancestral inference. I. The problem and the method.. https://doi.org/10.1111/j.1469-1809.1978.tb00934.x

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related citations

PubMed1992

Effects of demographic and ethnohistorical factors on average heterozygosities of South Amerindians.

Recent investigations have shown that average within-Tupi genetic distances differ from within-Carib distances, which is possibly due to differences in effective size of the populations belonging to these two linguistic stocks of South American tribes. The aim of this paper is to verify the influence of demographic factors and of interpopulation contacts on the degree of intragroup genetic variability of 18 South American native groups (eight Carib, seven Tupi, and three Gê). The mean per locus per individual heterozygosity (Hm) was studied for seven polymorphic systems and the distance from the centroid rii on Hm was evaluated with regression analysis according to Harpending and Ward's model. Data on intergroup contacts among the populations since the end of the eighteenth century were collected from an extensive review of the ethnohistorical literature. The level of Hm of the three linguistic stocks did not differ, which suggests a homogeneous within-group variation for these groups. In addition, there was no association between gene diversity and population size. On the other hand, demographic size correlated with rii, which suggest that gene frequencies in groups of larger populations more closely resemble the average gene frequencies of native South Americans. Values of rii differed between the stocks, and the average distance from the centroid of the Carib was about 2.6 times greater than that of the Tupi, in accordance with previous genetic distance analysis. It should also be emphasized that there was an important correlation between mean heterozygosity and the degree of historical intertribal contacts. This constitutes a particularly significant finding, suggesting the basic role of intertribal gene flow of the past two centuries on the level of present genetic variability of South American tribes.

Gene Frequency↗

PubMed1992

Mutation analysis of phenylketonuria in Spain: prevalence of two Mediterranean mutations.

We have screened seven Spanish phenylketonuric (PKU) families for the most prevalent Mediterranean and Caucasian mutations, and have subsequently found mutations P281L and IVS10. We have analyzed these two mutations in 23 of our patients. The frequencies found correspond to those of Mediterranean countries, such as Italy. This is the first report of a mutation analysis in the Spanish PKU population.

Gene Frequency↗

PubMed1992

Asymptotic rates of growth of the extinction probability of a mutant gene.

We prove that a result of Haldane (1927) that relates the asymptotic behaviour of the extinction probability of a slightly supercritical Poisson branching process to the mean number of offspring is true for a general Bienaymé-Galton-Watson branching process, provided that the second derivatives of the probability-generating functions converge uniformly to a non-zero limit. We show also by examples that such a result is true more widely than our proof suggests and exhibit some counter-examples.

Gene Frequency↗