Metaphase and meiotic chromosomes, synaptonemal complexes (SC) of the lizard Zootoca vivipara

Resumo

Somatic mitotic and meiotic chromosomes at the pachytene and at the metaphase I of the males of the viviparous lizard, Zootoca vivipara (Lichtenstein, 1823), from northwestern Russia, belonging to the Russian form of Z. v. vivipara, are examined. The spreading of synaptonemal complexes (SC) of their chromosomes are obtained and analyzed for the first time. Eighteen SC are observed, including SC of the Z₁Z₁ (pairs 5 or 6) and the Z₂Z₂ (pair 13) sex chromosomes. Characteristics of SC are compared with the number and the shape of bivalents and with those of the karyotype structure. In the studied Russian form of Z. v. vivipara, the length ratios of bivalents correlate with that of mitotic chromosomes (2n = 36); however, some specificity in the morphology of SC of the Z₁Z₁ sex chromosomes is reported in this article.