[Karyotypic instability of peripheral blood lymphocytes in cows Bos taurus L. infected with bovine leukemia virus].

Chromosomal aberrations (CAs), sister-chromatid exchanges (SCEs), aneuploidy and proliferative potential (PP) were investigated in peripheral blood lymphocytes of healthy cows (control group-C), BLV-(bovine leucosis virus)-infected cattle without hematological abnormalities (RID--seropositive group (I) and affected with leucaemia (lymphocytosis (LC), lymphoma (L)). Nonrandom chromosomal (marker) aberrations were not found in the cow group at stage LC. The levels of aneuploidy and SCEs increased in the cow group at stage L compared to the cow group at stage I.

[Heterochromatin and euchromatin regions in the chromosomes of various representatives of the subfamily Bovinae].

Heterochromatin distribution was studied in three species of subfamily Bovinae: bison (Bison bison), European bison (Bison bonasus), and gayal (Bos frontalis). In all of the studied species, C- and CMA3-banding and in situ hybridization with satellite DNAII (satDNAII) revealed the conservative distribution of heterochromatic regions in autosomes; sex chromosomes did not contain the classical constitutive heterochromatin. The Y chromosome was the most variable element of the karyotypes of both bison species and the gayal.

[Patterns in the condensation of bovine chromosomes in the prophase-late metaphase of mitosis].

A comparative analysis of Bos taurus L. cytogenetic maps of different resolution levels was used to study principles of fusion R(G)-bands during chromosome condensation from prophase to the late metaphase. Three different types of fusion have been demonstrated, differing in quantity of interacting bands and fusion mechanism.