中文摘要：

【目的】基于微卫星标记特点，采用计算机模拟技术，探讨畜禽保种群遗传多样性的变化过程。【方法】选择30个均匀分布于基因组、具有4—10个等位基因的标记位点，位点间无相互作用；模拟产生的畜禽保种群公母比例为1：5、随机交配、各家系随机等量留种、群体规模保持世代恒定，世代问无重叠，群体有效大小分别为Ne=10、20、50、100和200，保种繁殖50个世代，1000次重复。采用多态性位点数（num-p）、平均等位基因数（他）、有效等位基因数（Ae）、观测基因杂合度（Ho）、期望杂合度（He）、稀有等位基因数（RA）、缺乏丰富位点数（NRP）作为遗传多样性度量指标。【结果】保种群体的遗传多样性总体趋势随保种世代而逐渐降低，不同群体规模遗传多样性的降低速度差异显著，相比基础群，胎值越大，num-p、Na、Ae、110、He和RA的下降速率越慢，且当90=100和200时，num-p基本维持50个世代不变，删则分别增加0．86％和2．49倍；而此值越大，NRP的增加速率越慢。【结论】遗传漂变导致了群体内遗传多样性的丢失。小群体中遗传漂变导致的遗传多样性丢失速度比大群体更高，发生在闭锁群体水平上的有效群体规模的减少将加快基因漂变速度，从而降低保种群体内的遗传多样性。

英文摘要：

[ Objective ] The changes of genetic diversity of domestic animals＇ genetic resources were studied by using computer simulation based on the characteristics of microsatellite markers. [Method] Thirty mark loci were chosen and they are equally distributed in the whole genome, and each locus has 4-10 alleles, no interactions between these loci. Computer simulation was based on the assumption that there was no gene mutation, selection ratio of male and female is 1 ： 5 and random mating was implemented in all generations, the generation was non-overlapping and the number of breeding animals was selected through mating by family in equality, effective population size （Ne） were 10, 20, 50, 100 and 200. The simulation experiment was carried out for 50 generations and 1000 repeats. The number of polymorphic loci （Num-p）, allele number （Na）, number of effective alleles （Ae）, observed heterozygosity （Ho）, expected heterozygosity （He）, number of rare alleles （RA）, number of non-rich polymorphic loci （NRP） were indicators as genetic diversity. [Result] The overall trend of genetic diversity of conservation populations was decreased over generations, and differences were significant as Ne changed. It was seen that larger values of Ne, the more slower descent rate of num-p, Na, Ae, Ho, He, and RA compared with the base population, and num-p basically maintained at 30, RA decreased by 0.86% and 2.49 times as Ne were 100 and 200. Moreover larger, the values of Ne, the slower increase rate of NRP. [Conclusion] Decreases in effective population size that occur at a closed population level will increase gene drift and reduce genetic diversity within conservation population.