基于RNA-seq技术的北京油鸡五趾性状关键基因鉴定及功能研究

The five-toe phenotype is one of the important traits for Beijing You chicken, which is similar to the preaxial polydactyly in humans. Because the genetic mechanism of five-toe is complicated and remains unknown, it is difficult to use this important representing character efficiently and accurately in practice. The objective of the present study was to find genes crucial for polydactyly in Beijing You chicken systematically using the transcriptomic data of the digital primordia from the five-toed and the four-toed chicken lines and combining results from genome-wide association studies for the first time. Then, the molecular regulation mechanism of five-toe character would be studied with the quantitative PCR and the wholemount in situ hybridization technologies. Further, the polymorphisms of these genes would be screened and association analysis would be performed. The results will serve as a tool to facilitate the molecular assisted breeding for the five-toe in Beijing You chicken and also will provide valuable insight into the genetic mechanism of polydactyly in humans.

五趾是北京油鸡的重要标识性状，与人类轴前多趾类似，然而由于其遗传基础复杂至今尚不明确，生产中亦无法加以应用实现五趾的快速准确选育。本研究拟以五趾油鸡和四趾油鸡脚趾原基为试验材料，首次利用转录组测序方法，再整合课题组前期全基因组关联分析结果，系统的研究影响北京油鸡五趾形成的关键基因；结合定量PCR和原位杂交技术阐明基因调控五趾性状的分子机制，并进一步开展基因的多态筛查与关联分析，为北京油鸡五趾性状的分子标记辅助育种工作奠定基础，为人类多趾的遗传研究提供新的思路。

五趾是北京油鸡重要的外观标识性状，与人类轴前多趾类似，遗传机理复杂。本项目利用四趾和五趾油鸡纯系作为试验群体，研究了不同趾数类型油鸡后肢肢芽组织不同部位的转录组，得到了30个在四/五趾类型差异表达基因，207个在肢芽不同部位差异表达的基因；进一步研究了9个基因的在4个发育阶段的时空表达规律，证明趾数发育是一个多基因共同调控的复杂过程，SHH基因在油鸡五趾形成中发挥重要作用。通过候选突变位点和油鸡趾数表型以及骨骼解剖学相关性分析，验证了2号染色体上rs80659072位点T突变是北京油鸡五趾形成的必要条件。同时针对这一位点建立了快速的分子检测方法，在北京油鸡育种中应用大大提高了北京油鸡品种一致性。