Рассмотрены современные данные о происхождении и биологическом значении В-хромосом растений и животных, их строении и эволюции, о динамике и полиморфизме. На примере некоторых видов животных и растений показана возможная роль популяционной изменчивости в варьировании морфологических типов и числа В-хромосом.

No abstract

To assess the ecotoxicity of low doses of dioxins is almost impossible without considering the in uence of real exposure conditions on these substances’ properties. The best approach to take these into account is the biomonitoring of the initial toxic e ects’ manifestation. We studied bank voles from population naturally exposed to dioxins, the summer-born adults and overwintered functional groups of animals di ered by dioxin body burden. Dioxin-free samples of a vivarium bank voles’ line served as a control. Initial e ects of ecotoxicity were characterized by transcriptional levels of genetic markers: ahr, cyp1a2, keap1, dnmt1, dnmt3a, dnmt3b, LINE-1 and B1-SINE. Summer-born functional group had signi cantly higher expression levels of ahr, keap1, dnmt3a and dnmt3b genes versus their control group. Overwintered functional group had elevated expression levels of cyp1a2 and keap1, but no changes were found versus controls for dnmt1, LINE-1 and SINE B1. The increased expression of marker genes in dioxin-exposed voles was quite well associated with toxic process’ mechanisms - their formation and progression under exposure of several generations to low sub-toxic doses. The data obtained will contribute to the development of a biomonitoring method for assessing the initial e ects of dioxin ecotoxicity.