关键词: 大仓鼠, 遗传多样性, 种群动态, 遗传距离, 生态适应, 随机扩增多态性DNA

Abstract: The genetic diversities of sex populations and age group populations of the Rat-like hamster ( Cricetulus triton) populations in 1998 and 1999 were studied by using randomly amplified polymorphic DNA (RAPD) method through the polymerase chain reaction (PCR) . The proportion of polymorphic loci , Shannon index and Nei's Index were used to describe the population genetic diversity. It was discovered that the genetic differentiation between male and female group populations was relatively small , while it was greater among four age group populations ; the genetic distance increased with increase of age gap ; the genetic diversity of juvenile group population was higher than that of older age group populations ; the genetic differentiation and difference of autumn population in 1999 were more apparent than that of 4 season populations in 1998. The genetic differentiation among age group populations supported the view that genetic structure experienced change even under the selection in micro2time scale. The higher genetic diversity in juvenile age group population supported the Ford hypothesis that the new born animals were genetically diversified , some with better qualities , and some with lower ones. However , under natural selection , the individuals with lower genetic qualities were eliminated. Thus , the juveniles with lower genetic qualities would be disappeared due to the increase in natural selection pressures , while the genetic diversities of adult or old individuals were gradually reduced.

Key words: Rat2like hamster ( Cricetulus triton), Genetic diversity, Population dynamic, Genetic distance, Ecological adaptation, Randomly amplified polymorphic DNA (RAPD)