[Intrapopulational differences of genome structures in two structures of salmon-like fishes].

The natural populations of salmon-like catadromous fishes usually include several percents of residual (dwarf) forms, which are 10-15 times smaller than normal forms. A comparative investigation of normal and residual forms in two species: Oncorhynchus nerka and Salvelinus malma (Salmoniformes order) was made by means of DNA molecular hybridization technique. The essential differences in reassociation kinetics was detected in DNA from normal and residual forms of both species. The genome sizes (kinetic complexity) of normal and residual forms are approximately the same. But some families of repetitive nucleotide sequences are represented by considerably different amount of copies. Intrapopulational differences of genome structures of normal and residual forms in both species seem to be more rough in respect to reassociation kinetic than corresponding interspecies differences between malma and nerka. Comparative analyses and reassociation kinetics for long and shrt DNA fragments imply "xenopus type" of nucleotide sequence organization in both species which is common for the majority of animal and plant genomes investigated.