Pseudo-Random Mating with Multiple Alleles

The conditions on the mating matrix associated with a stable equilibrium are specified for an autosomal locus with four alleles. An example illustrates how Hardy–Weinberg proportions are maintained with nonrandom mating. The ABO blood group provides an illustration.

A Misconception About the Hardy–Weinberg Law

The Hardy–Weinberg law of population genetics is usually associated with the notion of random mating of parents. A numerical example for a triallelic autosomal locus shows that an uncountable set of mating combinations can maintain Hardy–Weinberg proportions. Therefore, one cannot infer random mating in a population from the observation of Hardy–Weinberg equilibrium. The mating system which ensures that the genotypic distribution of offspring is the same as that of the parents is specified.

Plasma alkaline phosphatase polymer phism and it’s association with productivity in Iraqi fowl

Plasma alkaline phosphatase isozyme in Iraqi fowl was studied by acrylamide gel electrophoresis. Two phenotypes fast and slow, were observed. These two phenotypes have been shown to be controlled by one single autosomal locus with two allel AKPF and AKPS. The gene frequency of AKPS is dominant over the AKPF. The result indicated that gene frequency of AKPF in leghorn and new hamshire was more frequent than in local Iraqi birds. Birds of fast isozyme type had higher 90 – day's egg production and egg weights as compared to those with slow isozyme. It is concluded that the fast isozyme can be used as gene marker for spotting out pullets with high body weight sexual maturity, high egg production and high egg weight.

Deviations from Hardy–Weinberg proportions for multiple alleles under viability selection

SummaryDepartures of genotype frequencies from Hardy–Weinberg proportions (HWP) for a single autosomal locus due to viability selection in a random mating population have been studied only for the two-allele case. In this article, the analysis of deviations from HWP due to constant viability selection is extended to multiple alleles. The deviations for an autosomal locus with k alleles are measured by means of k fii fixation indices for homozygotes and k(k−1)/2 fij fixation indices for heterozygotes, and expressions are obtained for these indices (FIS statistics) under the multiallele viability model. Furthermore, expressions for fii and fij when the multiallele polymorphism is at stable equilibrium are also derived and it is demonstrated that the pattern of multiallele Hardy–Weinberg deviations at equilibrium is characterized by a global heterozygote excess and a deficiency of each of the homozygotes. This pattern may be useful for detecting whether a given multiallelic polymorphism is at stable equilibrium in the population due to viability selection. An analysis of Hardy–Weinberg deviations from published data for the three-allele polymorphism at the β-globin locus in human populations from West Africa is presented for illustration.