On some theoretical studies on gene differentiation in natural populations

Different mathematical approaches to study the extent of genetic variation of natural populations are reviewed. The modern understanding of the gene structure permits new interpretations of existing concepts like fixation or inbreeding. A more recent measure of genic divergence, which at molecular level is designed to measure net codon differences is also seen to be related with gene diversity in a substructed population. It is argued that such variations are produced and preserved possibly by simultaneous action of migration, mutation, selection and random genetic drift. At the present moment, it is very difficult to isolate the effect of each factor because of varying degrees of variation at the different gene sites and between different sets of populations.