Roslik G.V., Kartavtseva I.V., Gorobeyko U.V.
Amurian zoological journal 2024; 16(2): 334-345
Widespread in the Russian Far East, the Apodemus peninsulae species is characterized by chromosomal polymorphism. It develops due to additional (or B) chromosomes in their karyotype. Additional chromosomes have a different number, size and morphology. This paper reports the results of karyotyping of animals from an of mixed larch and broad-leaved forests in the valley of the Amazar river. It also provides a comparative analysis of the karyotypes of newly studied and previously studied mice from amountain forest and forest-steppe areas of the Shilka and Onon river basins of the Zabaykalsky Krai. Variations in B chromosome numbers (1-9) were similar in most samples from this region. In mice of the Amazar river valley up to five variants of B chromosome morphotypes have been identified, namely: macro (medium metacentric, small submeta- and metacentric), mini and micro B chromosomes (Bs). Micro B chromosomes prevailed among all other morphotypes, both in the mice studied in this work and in other samples from the Zabaykalsky Krai. In the A. peninsulae populations of the Shilka and Onon river basins, from two to four variants of B chromosome morphotypes were found. Apparently, these populations are marked by an ‘impoverishment’ of morphotypic diversity compared to the Amazar river valley. However, the reasons for the decrease in the diversity of morphotypes against a relative constancy of variations in the numbers of Bs in animals of the Zabaykalsky Krai are not completely clear and require additional research.
