中国部分鸡种B-G基因SNP和Indel

鸡的MHC基因家族中B-G基因与鸡抗病性有关，通过研究与抗病有关的B G基因的多态性可以从根本上提高鸡抵抗疾病的能力，进而为抗病育种奠定基础。试验对25个鸡种基因组DNA进行目标捕获测序，以NCBI中Gallus gallus的B G基因序列为参考，利用MEGA6软件进行不同鸡种基因序列比对，分析B-G基因外显子和内含子中的SNPs和Indels以及氨基酸的变化，最后制作进化树。结果表明，25个鸡种中外显子存在8个SNPs、19个Indels，内含子有67个SNPs、327个Indels；同时氨基酸序列也呈现出相应的多态性，中国地方鸡种也表现出丰富的遗传多样性。来航鸡、仙居鸡、隐性白羽鸡的B-G基因存在丰富的多态性；来航鸡在进化树上单独为一类，藏鸡、文昌鸡由于地理位置因素也分别为单独一类；现代肉鸡中罗斯与隐性白羽鸡聚为一类；不同类型的中国地方鸡种间同源性较小。中国地方鸡种B G基因存在多源性进化以及丰富的遗传多样性，进而产生抗病性差异。

SNP and Indel analysis of B G gene of some Chinese chicken breeds

B-G gene of the MHC families is related to the traits of disease resistance in chicken breeds. Investigation on the polymorphism of B-G genes can fundamentally improve the chickens disease resistance， and then lay a foundation for resistance breeding. In this study， the DNA samples of 25 chicken breeds were used by target capture sequencing method for gene sequencing. Considering B-G gene sequence of Gallus gallus as the reference， we used MEGA6 software for gene analysis to seek out single nucleotide polymorphism (SNP)， insertion deletion (Indel) and the changes of amino acid， and finally constructed the evolutionary tree. The results revealed that exons had 8 SNPs， 19 Indels and introns had 67 SNPs， 327 Indels in 25 chicken breeds. Amino acids also presented certain polymorphisms and local breeds showed high degree of genetic diversity. This method provided abundant B-G genotypes in the chickens， such as recessive white chicken， Xianju chicken， Leghorns chicken. Leghorns chicken was in separate evolutionary tree for category. Tibetan chickens and Wenchang chickens were also separately categorized due to the geographical location factor. Rose in modern poultry and recessive white chickens gathered for one class， but homology between different types of Chinese local breeds were smaller. The above experiments showed that there were several origins and plenty of genetic diversities of B-G gene， which resulted in different disease resistance in Chinese indigenous breeds.