A comparative analysis of allozyme variability in vertebrate animals]

Comparative analysis of levels of the allozymic variation in the vertebrates is conducted using evaluation of a) within population heterozygosity of ferment coding homologous loci, b) average (per each species) allele frequencies of homologous loci, and c) overall sample of the loci being analyzed. It is established that amphibians and reptiles are characterized by the highest, birds and mammals--by the lowest, and fishes--by the middle level of genetic diversity. The diversity of genetic systems, if the constant heterozygosity of duplicated loci is taken into consideration, decreases from fishes to mammals and from cold-blooded to warm-blooded vertebrates. This tendency could be considered as an extrapolation of the "progressive specialization" rule on molecular level. Three basic factors determining certain level of genetic diversity of a species are acknowledged position in the phylogenetic system, population structure, and level of introgressive hybridization. From methodological viewpoint, evaluation of the genetic diversity by homologous loci seems to be most valid in comparative studies.