Big Hamster (tscherskia Triton) Populations, Genetic Variation And Ecological Adaptation Research

The genomic DNA of the greater long-tailed hamster (Tscherskia triton) extracted from the livers which are immersed in formalin, is amplified by 6 pairs of primers to detect SNPs , in order to study the variation of genetic diversity of the greater long-tailed hamster of different years. For the livers have been immersed in formalin for about 20 years, the method of extraction of DNA must be optimized repeatedly to satisfy the demand of the later experiment. And the primers chosen from 72 pairs of primers have the merits of high efficiency , abundant polymorphism and can be amplified stably. The segments amplified by the primers which are all about 500～600bp are cloned and sequenced . According to the analysis of DAMBE, DnaSP4.10 and MEGA3.10 , different numbers of SNPs exist in populations of different years and seasonal populations. The genetic diversity among 10 populations between 1984～1988 can be arrayed as follows: 86S>86A>85S>84S>85A>84A>87S>87A> 88S>88A.The analysis of UPGMA suggested that there are differences between 10 populations, though the differences are not significant. By synthetizing all the results , we can draw the conclusions as follows:1. Optimize the method of the genomic DNA extraction from the sample immersed in formalin.2. Select 6 pairs of primers including 5 pairs of primers designed according to Primer 5.0. The primers can amplified the genomic DNA segments stalbly and the segments amplified which are all about 550bp have the merits of the high efficency,abundant polymorphism, and can be amplified reapeatedly.3. The ecological adaptablity and the genetic regulation of the greater long-tailed hamster:a. The genetic diversity in spring populations tends to be higher than in autumn populations. This result supports the " reproduction —dispersal balance " hypotheses. The main idea of the hypotheses is that the temporal genetic diversity of population in a sample area is determined by both reproduction and dispersal.b. The genetic diversity of break-out-year populations tends to be higher than in low-quqantity-year populations . This result accord to the Ford hypotheses .Ford believed that when the population breaks out, because the natural selection is weaker, the hereditary variation in intrapopulation increases, but when the quantity of the population reaches certain density , the natural selection turns severely ,and the variation decreases.