A Century of Hardy–Weinberg Equilibrium

Abstract

Hardy–Weinberg equilibrium (HWE) is the state of the genotypic frequency of two alleles of one autosomal gene locus after one discrete generation of random mating in an indefinitely large population: if the alleles areAandawith frequenciespandq(=1-p), then the equilibrium gene frequencies are simplypandqand the equilibrium genotypic frequencies forAA,Aaandaaarep2, 2pqandq2. It was independently identified in 1908 by G. H. Hardy and W. Weinberg after earlier attempts by W. E. Castle and K. Pearson. Weinberg, well known for pioneering studies of twins, made many important contributions to genetics, especially human genetics. Existence of this equilibrium provides a reference point against which the effects of selection, linkage, mutation, inbreeding and chance can be detected and estimated. Its discovery marked the initiation of population genetics.

SNP-guided identification of monoallelic DNA-methylation events from enrichment-based sequencing data

“…the Hardy-Weinberg equilibrium, in a parental-independent and genome-wide manner. This theory states that in a large random-mating population with no selection, mutation or migration both the allele and genotype frequencies of a gene locus with two alleles are constant from generation to generation, and furthermore, that there is a simple relationship between these allele and genotype frequencies: if the alleles are A and a with frequencies p and q (= 1 − p), respectively, then at equilibrium the genotype frequencies of AA, Aa and aa are p 2 , 2pq and q 2 , respectively (22).…”

SNP-guided identification of monoallelic DNA-methylation events from enrichment-based sequencing data

“…the Hardy–Weinberg equilibrium, in a parental-independent and genome-wide manner. This theory states that in a large random-mating population with no selection, mutation or migration both the allele and genotype frequencies of a gene locus with two alleles are constant from generation to generation, and furthermore, that there is a simple relationship between these allele and genotype frequencies: if the alleles are A and a with frequencies p and q (= 1 − p ), respectively, then at equilibrium the genotype frequencies of AA , Aa and aa are p 2 , 2 pq and q 2 , respectively (22). …”

Detection and characterization of interleukin-6 gene variants in Canis familiaris: Association studies with periodontal disease

“…We found a deviation from Hardy-Weinberg equilibrium in the group of PD cases for I/5_g.105 G N A genotypes. Hardy-Weinberg equilibrium is influenced by a series of features regarding the tested population, for example: sample population size, random mating, no migration, no genetic drift and no selection taking place (Mayo, 2008). Thus, our results could be due to chance or violation of these assumptions, being the possibility of genotyping errors lower, since all genotypes were detected by direct sequencing.…”