不同公母比例下威宁牛原位保种群体遗传漂变的计算机模拟

Computer Simulation of Genetic Drift in the in-situ Conservation Population of Weining Cattle under Different Male-female Ratios

通过计算机模拟方法研究威宁牛原位保种群在假定实行随机留种、随机交配、世代不重叠、群体间个体无迁移、整个保种过程中基因不发生突变的情况下50个世代中不同公母比例对群体内等位基因频率和基因型频率的影响。结果表明:公母比例越大(1∶99、1∶49),由于世代间随机遗传漂变而导致的等位基因A_(1)的频率达到极大值(A_(1)=1.0000)被固定的世代就越早出现、基因型A_(1)A_(1)、A_(1)A_(2)、A_(2)A_(2)的频率达到极值(1或0)的世代数也越早,保种效果较差;公母比例越小(1∶4、1∶9、1∶19),等位基因A_(1)被固定、3种基因型频率达到极值(1或0)的风险就越低,保种效果也越好。

Computer simulation was used to investigate the effects on allele frequency and genotype frequency in the%in-situ%conservation population of Weining cattle with different male-female ratios among 50 generations,assuming that there was no gene mutation and individual immigration between populations throughout the conservation process.Random selection and mating,and non-overlapping were implemented in all generations.The results showed that the larger the ratio of male to female(1∶99,1∶49),the earlier the fixed generation appeared due to random genetic drift between generations,and the earlier the frequency of allele A_(1)reached to its maximum(A_(1)=1.0000).The earlier the generation with genotype A_(1)A_(1),A_(1)A_(2),and A_(2)A_(2)reached its maximum(1 or 0),the poorer the conservation effect was;The smaller the male to female ratio(1∶4,1∶9,1∶19),the lower the risk of allele A_(1)being fixed and the frequency of the three genotypes(A_(1)A_(1)、A_(1)A_(2)、A_(2)A_(2))reached the extreme(1 or 0),and the better the conservation effect was.