Variations in Chromosome Synapsis at Meiotic Prophase I of Mole Voles <i>Ellobius</i> <i>tancrei</i> Heterozygous for Robertsonian Translocations

Abstract

We have shown that different combinations of meiotic configurations (different number of trivalents and different chromosome chain structure) in the same individual can be formed in heterozygotes with the Robertsonian translocations in the meiotic prophase I. Two types of experimental hybrids of the eastern mole vole Ellobius tancrei which are heterozygous for four Robertsonian translocations were studied here. Instead of the expected four trivalents, different types of meiotic configurations at the pachytena stage up to 10-element chains were identified. We suggest that the probability of passing meiosis in different cells depends on the structure of the formed chains and possibility of their correction. Such variations in chromosome synapsis during multivalent formation may lead to a decrease in gametes production but not to a complete stop of gametogenesis, which provides the background for the maintenance of Robertsonian translocations in the population.