参考家系鸡黑素皮质素受体3基因多态性与体重关系研究

Studies of Relationship Between the Melanocortin-3 Receptor Gene and Body Weight in Chicken for High and Low Weight Lines' Intercross

鼠遗传学研究显示黑素皮质素受体 3(melanocortin 3receptor,MC3R)和MC4R在能量平衡控制中具有互补作用。敲除MC3R基因鼠表现为独有的代谢综合征和增加脂肪重量。以 8周龄高体重或低体重独立选择的高体重系 (highweight,HW)和低体重系 (lowweight,LW)白洛克鸡 3代参考家系群体作为实验材料 ,发现了 5个新的MC3R基因单核苷酸多态性 (singlenucleotidepolymorphisms,SNPs) ;建立了基于限制性内切酶DdeⅠ的MC3R基因型的PCR RFLP分子检测方法。方差分析结果显示MC3R基因型显著影响公鸡和母鸡的体重 ,以及公鸡腹脂含量。

Genetic studies in mice have demonstrated a complementary role for the melanocortin 3 receptor ( MC3R ) and MC4R in the control of energy balance. Knockout of the MC3R in mice revealed an exclusively metabolic syndrome and increased fat mass. In the present study, we found a total of 5 novel single nucleotide polymorphisms (SNPs) of the MC3R gene in the chickens of high weight (HW) and low weight (LW) lines from divergently selected for high or low body weight at 8 weeks of age in White Plymouth Rock. Only one of the 5 SNPs led to amino acid substitution (Leu→Arg) in HW and LW lines animals:a T/G substitution at nucleotide (nt) position 452 of coding sequence. Three of the 5 SNPs disdinguished the birds from HW and LW lines:an A/G substitution at nt position 549 in LW line, an A/G substitution at nt position 882 in HW line, and a C/T substitution at nt position 894 in LW line, respectively. Another SNP was presented only in one of two HW line animals:a C/T substitution at nt position 564. Of the 5 SNPs, only A/G polymorphism at nt position 549 is located within a DdeⅠ restriction enzyme recognition site. We designed a PCR RFLP test based on the enzyme DdeⅠ and screened the chickens for HW and LW lines' intercross. Analysis of variance revealed a significant influence of the MC3R genotype on body weight in the chickens for both sex and abdominal fat mass in male chickens. The result suggests that the MC3R as a candidate gene can explain significant difference for body weight in the intercross chickens.