用放射杂交板定位鸡的MC4R基因以及其在鸡和人染色体上同源区的比较分析

黑素皮质素受体(melanocortin-4 receptor，MC4R)基因的突变与猪、鼠和人等的食欲、肥胖和生长有关联性，然而对鸡的MC4R基因的功能却知之甚少。为了确定鸡的MC4R基因在染色体上的位置，使用鸡-仓鼠杂交板(ChickRH6)做了该基因的定位工作。通过扩增ChickRH6杂交板上的93个样品，然后经整合分析将mC4R基因定位在2号染色体上的标记MCW0062、BCL2和OVY附近，即2q12。这个连锁图上的5个标记基于两点分析与MC4R的LOD值都大于5。同时，以MC4R基因为标记做了鸡和人的染色体比较分析。结果显示鸡的2号染色体(GGA2)和人的18号染色体(HSA18)存在同源区，且基因BCL2和肥胖基因(obesity)位于MC4R基因附近。推测鸡的MC4R基因与人的MC4R基因可能具有相似的功能。该研究揭示了鸡和人MC4R基因的染色体分布，并用杂交放射板将鸡的MC4R基因定位在2号染色体的12区带。

Chromosomal Mapping of Chicken MC4R Using a Radiation Hybrid Panel and the Comparative Analysis of the Gene Homologous Regions Between Chicken and Human Chromosome

Mutations of the melanocortin-4 receptor (MC4R) are associated with hyperphagia,obesity,and accelerated longitudinal growth in pig,mice and human.However,little is known about the functions of this gene in chicken.To map the MC4R gene in Chicken chromosome,we used a 6 000 rads chicken-hamastr radiation hybrid panel (ChikenRH6).PCR of samples from the ChikenRH6 revealed the location of the MC4R gene to be nearby markers MCW0062,BCL2 and OVY on chromosome 2q12.Five markers were placed into a single linkage group based on two-point analysis with a LOD score of greater than 5.At the same time,the MC4R gene was selected as marker to compare DNA sequence between chicken and human chromosome.The result shows there are the same homologous regions between chicken chromosome 2 (GGA2) and human chromosome 18 (HSA18),and we found that the genes BCL2 and obesity are located in the near regions of MC4R on human chromosome 18.So we can reduce that the chicken MC4R gene maybe there are the same functions with the human MC4R gene.Overall,this work reveals widespread chromosome rearrangements of MC4R between chicken and human genomes,and mappings the chicken MC4R gene on 2q12 by a RH panel.