盐津乌骨鸡mtDNA D-loop区遗传多样性及其保种效果分析

Genetic Diversity and Conservation Effect of Yanjin Black-bone Chicken Based on Genetic Marker of mtDNA D-loop Region

为阐明盐津乌骨鸡的群体遗传背景和评估、监测其保种效果,采用PCR产物直接测序对保种群样品进行了mtDNA控制区的变异检测,并结合已发表的云南其他地方鸡数据进行了群体遗传学分析。结果表明,在所检测的2005年样品中,共发现40个核苷酸变异位点,其中32个为简约信息位点,8个为单一信息位点;共定义27种单倍型,单倍型多样度为0.939,核苷酸多样度为0.01595,群体内遗传距离为0.016;包含A、B、C、E、F和G等6个母系世系,所占比例分别为35.44%、3.80%、6.33%、10.13%、6.33%和37.97%。在所检测的2018年样品中,发现24个核苷酸多态位点,其中5个为单一信息位点,19个为简约信息位点;共发现到13种单倍型,单倍型多样度为0.847,核苷酸多样度为0.01118,群体内遗传距离为0.011;包含A、B、E和G等4个母系世系,所占比例分别为31.67%、10.00%、50.00%和8.33%。研究结果提示,两种样品群体遗传组成存在较大差异,2018年保种群遗传多样性水平比2005年的显著下降,群体中母系世系减少,存在较大比例外来鸡种的基因渗入,保种效果欠佳。

In order to clarify the population genetic background of Yanjin black-bone chicken,and evaluate and monitor its conservation effect,the variation of the mtDNA control region of this chicken sampled in 2005 and 2018 was detected by direct sequencing of PCR products,and the population genetic analysis was carried out combined with the published data of Yunnan local chickens.In the samples collected in 2005,a total of 40 polymorphic sites were found,of which 8 were singleton variable sites and 32 were parsimony informative sites.And 27 haplotypes were defined based on these polymorphic sites.The haplotype diversity(H),nucleotide diversity(π)and genetic distance within population were 0.939,0.01595 and 0.016,respectively.The samples included 6 maternal lineages A,B,C,E,F and G,with the proportion of 35.44%,3.80%,6.33%,10.13%,6.33%and 37.97%,respectively.Among the samples collected in 2018,a total of 24 variable sites were found,of which 5 were singleton variable sites and 19 were parsimony informative sites.A total of 13 haplotypes were defined based on these variable sites.In the samples assayed,the haplotype diversity,nucleotide diversity and genetic distance within the population were 0.847,0.01118 and 0.011,respectively.There were 4 maternal lineages A,B,E and G found in the samples,with the proportion of 31.67%,10.00%,50.00%and 8.33%,respectively.The results indicate that there are significant differences in genetic composition between the samples of the 2018 and the 2005.The level of genetic diversity of the conservation population in 2018 was significantly lower than that of conservation population in 2005,and the maternal line in conservation population in 2018 decreased.Moreover,the chicken has a large proportion of gene penetration of foreign chicken breeds,and the preservation effect is poor.