POPULATION GENETICS

Abstract RésuméPopulation Genetics is the branch of genetics concerned with the study of variations in allelic and genotypic frequencies, in space and time, at the level of a particular gene or several genes in one or more populations of the same species. Knowing full well that all the individuals of a given species are interspecific and therefore capable of exchanging genes between them, the result is a permanent homogenising genetic mixing of varying degrees of magnitude depending on the geographical proximity of the individuals and the possible presence of physical barriers impermeable to genetic exchange by migration between geographically isolated populations. It is easily demonstrated using simple mathematical models that, in the absence of choice of breeding partner (notion of panmixing), mutations and selection pressures, migration and genetic drift, allelic and genotypic frequencies remain constant from one generation to the next, at least in populations of very high numbers: this is the law of panmictic equilibrium more commonly known as the Hardy-Weinberg law.