不同类型肉鸡线粒体单倍型与遗传起源研究

旨在探讨鸡线粒体D-loop区单倍型特性以及与生长速度的相关性，并分析其遗传起源。选取不同类型肉鸡品种（配套系）6个，测定其生产性能，并对6个群体共计314个个体线粒体D-loop区全长进行测序，分析其单倍型特性；同时与不同红色原鸡亚种进行聚类，分析其母系起源。结果显示，6个群体D-loop区全序列共检测到37个突变位点，构成40种单倍型，分为A、B、C和E 4个单倍型群，其中AA肉鸡、罗斯308、禽雁麻鸡和裕禾1号肉鸡主要为E单倍型，占比分别为85.92%、50.00%、100.00%和70.21%；园丰麻鸡2号和港丰瑶黑麻鸡E单倍型占比相对较低，分别为15.00%和22.39%，园丰麻鸡2号B单倍型含量最高，占比66.67%，港丰瑶黑麻鸡C单倍型含量最高，占比40.30%。相关性分析显示，初生重与E单倍型比例之间呈极显著正相关（P<0.01），与A、B和C单倍型比例之间均呈负相关；E单倍型比例与公母平均体重约1.8 kg时日龄之间呈显著负相关（P<0.05），而与公母平均体重约1.8 kg时饲料转化比之间呈极显著负相关（P<0.01）。聚类分析显示，A、B单倍型所有个体均与原鸡滇南亚种聚为一枝；E单倍型所有个体均与原鸡印度亚种聚为一枝；C单倍型所有个体与原鸡印度亚种、滇南亚种、指名亚种以及印尼亚种交叉聚为一类。结果提示，线粒体单倍型与肉鸡生长速度之间相关显著，E单倍型与肉鸡生长速度具有较强的正相关；我国家鸡群体母系起源丰富，但主要起源于原鸡滇南亚种。

Studies on Mitochondrial Haplotype and Genetic Origins of Different Types Broilers

The aim of this study was to investigate the haplotype characteristics of the mitochondrial D-loop region in chickens and its correlation with growth rate, and to analyze its genetic origin. Six different types of broiler breeds (synthetic lines) were selected to determine their production performance. The full length of the mitochondrial D-loop region of 314 individuals from the 6 groups were sequenced to analyze their haplotype characteristics, and clustered with different jungle fowl subspecies to analyze their maternal origin. The results showed that a total of 37 variant loci were detected in the whole sequences of D-loop regions of the 6 populations, constituting 40 haplotypes, and were divided into 4 haplotype groups A, B, C and E. Among them, AA broilers, Ross 308, Qinyan partridge chicken and Yuhe No.1 broilers were all mainly E haplotypes, accounting for 85.92%, 50.00%, 100.00% and 70.21%, respectively. Yuanfeng partridge chicken No.2 was mainly B haplotype (66.67%) and Gangfeng yao black partridge chicken was mainly C haplotypes (40.30%). While the proportions of E haplotype in the two chicken populations were relatively low, with 15.00% and 22.39%, respectively. Correlation analysis showed that birth weight was positively correlated with the proportion of haplotype E (P<0.01), and negatively correlated with the proportion of haplotype A, B and C. There was a significantly negative correlation between the ratio of E haplotype and the age of the average body weight of males and females at about 1.8 kg (P<0.05). And there was a very significantly negative correlation between the ratio of E haplotype and the feed conversion ratio of average body weight of males and females at about 1.8 kg (P<0.01). Cluster analysis showed that all individuals with A and B haplotypes clustered with gallus gallus spadiceus, all individuals with E haplotypes clustered with gallus gallus murgha, all individuals with C haplotypes clustered with gallus gallus murghi, gallus gallus spadiceus, gallus gallus gallus and gallus gallus bankiva. The results indicated that there is a significant correlation between mitochondrial haplotype and the growth rate of broilers, E haplotype had a strong positive correlation with broiler growth rate. The local chicken breeds in China had multiple maternal origins, mainly originated from Gallus gallus spadiceus.