Karyotype, chromosome structure, reproductive modalities of three Southern Eurasian populations of the common lacertid lizard, Zootoca vivipara (Jacquin, 1787)

Abstract

According to a hypothesis of the evolution of viviparity the lacertid lizard Zootoca vivipara, rare relict oviparous populations of the species might occur in south - ern-eastern part of its distribution area. Such a hypothesis has been verified by compar - ing the karyotype, chromosome structure, and reproductive modality of three popula - tions of south-eastern part of Russia, including Altai and neighbouring regions, where small territories remained isolated during the Pleistocene cooling and where Pleistoce - nic fossils of Z. vivipara have been found. The chromosomal study was carried out by conventional staining method and banding methods, namely C-banding and sequential staining of C-banding+ fluorochromes, CMA 3 and DAPI. All studied females displayed viviparous reproductive modality and showed a karyotype of 2N = 35 acrocentric chro - mosomes, with a Z1Z2W sex chromosome system. Chromosome W was subtelocentric . No inter-population variability on karyotype and heterochromatin distribution and composition was observed. From the obtained data the three studied south-eastern Russian viviparous populations belong to the Russian viviparous form of Z. v. vivipara.