[Chromosomal polymorphism in 2 synanthropous populations of the gray rat (Rattus norwegicus Berk.)].
Chromosome sets of 155 Norway rats from Ufa and 86 from Sverdlovsk are studied. The polymorphism for 3rd and 12th chromosomes is observed in both populations. Frequencies of different morphological forms of the 3rd chromosome are practically the same for Ufa and Sverdlovsk (over 90% of animals are homozygous for the telocentric, about 4-6% are heterozygous, homozygous for the subtelocentric rats are absent). The frequency of the telocentric form of the 12th chromosome in the Sverdlovsk population is significantly higher than in the Ufa one: there are 94,8% homozygous for the subtelocentric rats in Ufa, while in Sverdlovsk 83,7; 5,2 and 15,1% of the animals respectively are heterozygous; no homozygous for the telocentric rats were discovered in Ufa, and in Sverdlovsk they comprised 1,2%. The average size of litter of heterozygous for 3rd or 12th autosome females is by 30% lower than that of homozygous for the telocentric chromosome 3 and the subtelocentric chromosome 12 females. It may be suggested that the telocentric form of the 3rd chromosome supplants its subtelocentric form in populations investigated.
D000818:Animals; D002875:Chromosomes; D005260:Female; D007621:Karyotyping; D008297:Male; D011110:Polymorphism, Genetic; D051381:Rats; D014586:USSR
Khromosomnyĭ polimorfizm v dvukh sinantropnykh populiatsiiakh seroĭ krysy (Rattus norwegicus Berk)