中国地方鸡种遗传多样性和品种贡献率分析

Analysis about Genetic Diversity and Contribution Rate of Chinese Indigenous Chicken Breeds

利用16个微卫星标记,计算10个地方鸡品种群体位点多态信息含量(PIC)、F-统计量、DA遗传距离,用以评价品种遗传多样性。并基于DA遗传距离采用NJ法构建系统进化树,通过分析其对品种间遗传关系的重建,检验DA遗传距离度量方法的可靠性,用以计算现实多样性和品种贡献率。结果表明:16个微卫星座位均为中度或高度多态位点(PIC>0.25,PIC>0.50),10个地方鸡种群体总近交系数(Fit)为0.147,群体间基因分化系数(Fst)为0.134,群体内近交系数(Fis)为0.015,且3个指标均达到显著水平(P<0.05)。DA遗传距离较为准确地反映了10个地方鸡品种间的系统进化。基于DA遗传距离获得的10个地方鸡品种群体现实多样性为1.7 932,茶花鸡的品种贡献率最大(16.59%),其次为固始鸡(14.01%)、白耳鸡(11.44%)、狼山鸡(11.34%)、北京油鸡(11.30%)、大骨鸡(8.90%)、仙居鸡(7.03%)、藏鸡(6.28%)、鹿苑鸡(5.81%),萧山鸡的品种贡献率(5.00%)最低。研究结果可为更有效地保护我国地方鸡种资源遗传多样性提供理论基础。

The polymorphism information content （PIC）, F-stasitics, DA genetic distances measured by 16 microsatellite markers, were used to assed the genetic diversity of ten Chinese indigenous chicken breeds. The evolutionary tree based on DA genetic distances using NJ method was also constructed. The reliability of DA genetic distance measured method was evaluated by analyzing the genetic relationship among the ten Chinese indigenous chicken breeds demonstrated in the evolutionary tree. DA genetic distance was used to calculate the extant diversity and breed contribution rate. The results showed PIC of all the loci were more than 0.25 or 0.50. The global heterozygote deficit across of all populations （Fit） amounted to14.7% （ P 〈 0.01 ）. The overall deficit of heterozygotes because of inbreeding within breeds amounted to 1.5% （ P 〈 0.05 ）. The ten local breeds were highly differentiated （Fst =13.4%, P 〈 0.01 ）. DA genetic distance better reflected the systematic evolution of the ten Chinese indigenous chicken breeds. The calculated extant diversity of the ten local breeds based on DA genetic distance was 1. 7932. The contribution rate of CHA （16.59%） was the highest, the next following were GUS （14.01%）, BAI （11.44%）, LAN （11.34%）, YOU （11.30%）, DAG （8.90%）, XIA （7.03%）, TIB （6.28%）, LUY （5.81%）, and XIS had the lowest contribution rate （5.00%）. These results could supply theories for more effectively conserving diversity of Chinese indigenous chicken breeds.