华南家鸡MHC-B区域复合微卫星位点LEI0258的遗传多样性与进化研究

Evaluation of Diversity and Evolution of the Microsatellite LEI0258 in Chicken MHC-B Region from South China

旨在应用MHC-B区域复合微卫星位点LEI0258研究华南家鸡的遗传多样性与进化历史。以华南地区和邻省家鸡及商品鸡为试验材料,对微卫星位点LEI0258进行基因分型和测序,分析其遗传多样性和构建中介网络图。结果表明,580份样品共检测到LEI0258的62个等位基因,长度范围为182~501bp,其中37个为首次发现。华南家鸡LEI0258保持着较高的遗传多样性水平,观察杂合度、期望杂合度和多态信息含量分别为0.813、0.960和0.957。中山沙栏鸡、文昌鸡和五华三黄鸡的遗传多样性水平明显高于广西三黄鸡。LEI0258的28个等位基因与27种已知MHC血清型相对应。基于LEI0258侧翼区变异信息的中介网络图将62个等位基因分为8条进化枝,其中3条进化枝同样存在于红原鸡中,提示华南家鸡主要起源于红原鸡。部分等位基因存在于特定鸡品种中,可作为品种鉴定的参考依据。结果提示,微卫星位点LEI0258适用于地方鸡群体遗传多样性、血清型鉴定、品种鉴定和进化研究。

The aim of the study was to investigate polymorphism and evolution in South China chickens by the tandem repeat LEI0258 located within the B region of the chicken major histocompatibility complex（MHC-B region）.Genotypes and sequences of LEI0258 were obtained from 12 Southern China chicken breeds and 2commercial chicken breeds,and then these data were used to analyze genetic diversity and construct median-joining network.A total of 62 alleles were defined by DNA sequencing ranged from 182 to 501bp in 580 samples,37of which was novel for these chicken breeds.The LEI0258 showed high levels of polymorphism in South China chickens,with0.813,0.960 and 0.957 for observed heterozygosity,expected heterozygosity and polymorphic information content,respectively.The Shalan,Wenchang and Wuhua Three-yellow chicken breeds had higher levels of genetic diversity than Guangxi Yellow chicken.Twenty-eight allelesof LEI0258 were corresponding to 27 available serotypes of MHC.The 62 alleles of LEI0258 were classified into 8clusters in median-joining network,based on the SNPs and indels found within the flanking sequences,and 3of which was found in red junglefowl,indicating that South China chicken mainly originated from red junglefowl.Some alleles existed in a certain chicken breed,which could be as a candidate marker for breed identification.The results suggest that LEI0258 can be used as a molecular marker for elucidate genetic diversity,serology and breed identification,evolution in indigenous chicken breeds.