Sheremetyeva I.N., Kartavtseva I.V., Chelomina G.N.
В издании Modern achievements in population, evolutionary and ecological genetics (MAPEEG – 2007): Program and Abstract of International Symposium
Год: 2007 Страницы: 36
The Far Eastern vole, Microtus fortis Buchner, 1889 is the most widespread species on the islands of the Peter Great Bay, Japan Sea except islands Stenin, Verkhovsky and Askold. Populations of this species are able to survive even on very small islands due to intrinsic mechanisms of population density regulation. Therefore, sizes of island population do not reach critically high levels (Katin 1989). The islands of the Peter Great Bay have a mainland origin and were connected with continent up to the last transgression of the sea. The time of their isolation is dated at 10–7 or 12–8 thousand years ago (Velizhanin 1976). Hence, the formation of the fauna of these islands descended into the last Holocene cold snap period. Thus, the above mentioned islands may represent a convenient model for studying the features of microevolutionary processes in small isolated populations of rodents. The study morphological (m), karyological (k), allozyme (a) and molecular genetic (m) dates of M. fortis from10 insular populations of the Peter the Great Bay: Russky (m=34, к=1, а=1, r-p=1 и s=1), Putyatin (m=79, к=5, а=5, r-p=5 и s=1), Popova (m=6, к=6, а=6, r-p=3 и s=2), Klikova (m=9, к=5, а=5, r-p=4 и s=1), Reineke (m=3, к=2, а=2, r-p=2 и s=1), Bolshoy Pelis (m=6), Rikorda (m=19, к=6, а=6, r-p=2 и s=1), Matveeva (m=34, к=14, а=14, r-p=5 и s=3), Skrebtsova (m=4), Lissiy (m=14, к=14, а=10 и s=2) show the morphological and genetical variability. Tree morphological types of individuals were specified. The first type include individuals from Islands Lissiy and Rikorda, the second type - Russky Island and Putyatin Island. This types statistically significant in upper tooth row length, condylobasal length and interorbital distance. The third type include individuals from Matveev Island. The animals from this island statistically significant in tail length, foot length, diastema length and zygomatic breadth. The kariological analysis of animals from islands proved to be similar to that shown previously for voles from the mainland of the Russian Far East: 2n=52 NF=64. Using electrophoretic analysis of ten enzyme systems and three proteins of non-enzyme nature for examination of the continental and island populations of the Far Eastern vole, we have identified in them 25 interpretable loci. In the animals examined, all the loci but one proved to be monomorphic. For instance, in the population of the Reineke Island, in addition to the major allele ESTplasma-3-a, we have recorded another allele of this locus, ESTplasma-3-b, in one out of two animals examined. In the Far Eastern vole population from Matveeva Island, allele ESTplasma-3-b was found in all 14 animals scored. Random amplified polymorphic DNA markers were used to estimate the level and pattern of genetic diversity in M. fortis populations from mainland and islands of the Russian Far East. No markers were found as for individual populations, so as for mainland or island voles in whole, however they appeared to be different in both their allele frequencies and microevolution mode based on correlation pleiad analysis. Besides, the island populations demonstrated a higher level of genetic differentiation among themselves, and each mainland population represented more species genetic diversity, than any population of islands. Nevertheless, exact test did not support belonging of both united mainland and united island populations to the same genetic unit (p=0.0025). RAPD data reliably differentiated voles of Matveeva Island, strongly differentiated on morphological traits, as the most distant among all local populations examined that did not exclude the island speciation event. In the tree derived from the DNA sequences, M. fortis forms a distinct clade with low intraspecific differentiation. However, the population from one of Matveeva Island tends to fix a rare haplotype.
