Vol 103, No 12 (2024)

Results of complex studies on unisexual and bisexual (parental) species, mainly of the genus Darevskia, have been generalized, including allozyme, mitochondrial (mt) DNA, nuclear microsatellite (ms) DNA analyses, combined with different molecular cytogenetic techniques, as well as in combination with environmental factors. Present complex research has confirmed the concept of hybridogeneous speciation of unisexual species of lizards elaborated in 1980 and based on three interrelated phenomena such as hybridization-unisexuality-polyploidy. At the same time, the selectivity (сonstraints) and rarety of successful hybridization are emphasized at present, these studies have confirmed ‘paternal’ and ‘maternal’ species of hybrid unisexual species, some phylogenetic constraints of successful hybridization, and the roles played by “specific genome properties” and sex chromosomes. The data obtained have extended our knowledge of the genetic diversity of hybrid unisexual species and the understanding of the evolutionary plasticity of hybrid genomes and meiosis modifications, emphasizing the roles played by suboptimal environmental factors during the origin of such species. Further experiments may provide promising information concerning regular trends in the hybridogeneous speciation of unisexual species from different groups of vertebrate animals.

Using a non-invasive approach, changes in the level of physiological stress in speckled ground squirrels (Spermophilus suslicus) relocated from a natural population to an outdoor enclosure were assessed. The enclosure of 0.16 ha in area provided ground squirrels with natural conditions and resources and was protected against predators. First, using the physiological test with ACTH injection, we validated a commercial ELISA kit for cortisol in blood serum (“OOO XEMA”, RF) for measuring a glucocorticoid response in fecal samples as an indicator of individual stress level. We collected faeces from ground squirrels immediately after capture in nature (to characterize a basal level of stress in the donor population), after transportation before release to the outdoor enclosure, three days after release, and after one month, before hibernation. Three days after relocation, the stress level in speckled ground squirrels was significantly lower than after transportation and did not differ significantly from the initial level in the donor population. The absence of a body mass loss in young animals after the relocation, the successful accumulation of fat before hibernation, and the high overwinter survival rate (72.5%) indicate the successful adaptation of speckled ground squirrels to a novel environment.

Based on a study of dental characteristics of the water vole genus Arvicola from 7 regions of Azerbaijan, captured in 1926–1965 and stored in the collection of the Institute of Zoology, Ministry of Science and Education of Azerbaijan, the range of variability of the tooth enamel differentiation index SDQ is determined. The index is calculated as the ratio of the thickness of leading to trailing cutting edges of the enamel prisms of the cheek tooth crowns. SDQ serves as a criterion for identifying chronospecies of Arvicola in the fossil record, and it has recently been proposed for diagnosing modern Eurasian and Persian water voles. As a result of measuring the SDQ index in 55 individuals from the Shemakha, Saatli, Imishli, Goygol (= Khanlar), Ordubad, and Adjikabul regions, the water voles are shown to have a plesiomorphic type of enamel differentiation, in which the SDQ index values are greater than 100. In the specimens under consideration, the values of SDQ indices assessed for the first lower and second upper teeth vary from 100 to 178. In contrast to the dimensional characteristics of the teeth, the index values do not demonstrate directional changes in postnatal development and retain the plesiomorphic pattern of dental enamel differentiation in all age classes distinguished by the degree of skull maturity. The results obtained confirm the difference in the dental characteristics of the water voles occurring in Azerbaijan from the Eurasian A. amphibius and the proximity to the west Asian water voles currently considered as an independent species or species group, A. persicus (Persian water vole). Revision of data on differential chromosome staining and an analysis of molecular markers, both mitochondrial and nuclear, are necessary to answer the question concerning the taxonomic status of water voles in Azerbaijan and other regions of Western Asia, where water voles with a negative type of differentiation of tooth enamel occur. Until a final decision is made on the taxonomic status, composition and distribution of the Persian water vole, the water voles of Azerbaijan with a plesiomorphic type of tooth enamel differentiation are proposed to be referred to as Arvicola cf. persicus.