Abstract
Chromosome polymorphism in Bulgarian populations of the striped field mouse (Apodemus agrarius Pallas, 1771) has been described. The diploid chromosome number is 2n=48 (NFa = 54). In the karyotype of 3 specimens from the Iskar region, the presence of an additional B chromosome has been established for the first time. The autosomes are 19 acrocentric pairs, continuously decreasing in size, and 4 pairs of bi-armed chromosomes, barely distinguishable by size and location of the centromere. Specimens with 3 pairs of metacentric chromosomes were firstly described in Bulgaria for the regions of Iskar and Omurtag. The localization of heterochromatin in the centromeric regions of the chromosomes, blocks of heterochromatin of different sizes, as well as intercalated bands, distinguishable in weakly spiraled chromosomes are found. Telomeric heterochromatin is present in the largest autosomal pair and in two of the middle-sized autosomal pairs. The largest and smallest pairs of be-armed chromosomes do not have centromeric heterochromatin, whereas all the other autosomal pairs do. The presence of a NOR in 6 chromosomal pairs is established. Two of the pairs exhibited pericentromeric NORs, whereas the other 4 displayed telomeric NORs. The karyotype analysis illustrates the chromosome and genome polymorphism of A. agrarius in Bulgarian populations.
Highlights
The field mouse Apodemus agrarius (Pallas, 1771) is widely spread in the temperate zone of Eurasia (Corbet, 1978)
In Bulgaria, the karyotype of the field mouse with 3 pairs of metacentric chromosomes was first described for the regions of Iskar (8 specimens) and Omurtag (3 specimens)
Additional chromosomes in the field mouse have only been established in the Far East and Russian populations so far (Kartavtseva, 1994; Kartavtseva, Pavlenko, 2000)
Summary
The field mouse Apodemus agrarius (Pallas, 1771) is widely spread in the temperate zone of Eurasia (Corbet, 1978). The Palearctic range of A. agrarius consists of two isolated tracts of land: European–Siberian and Far Eastern-Chinese (Karaseva et al, 1992; Panteleyev, 1998; Gliwicz, Kryštufek, 1999). The species is not found in Western Europe and has an unstable and dynamic western border of its European distribution (Kratochvil, 1976), reaching to the northern part of the Balaton lake and Eastern Austria, according to the latest studies (Spitzenberger, 1997). The southern border of the European area of the field mouse passes through Bulgaria. It is a relatively rare species in Bulgaria, with sparse populations that have a mosaic spread
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
