洪山鸡垂尾性状相关基因的定位及其功能研究

Hongshan chicken, as a Chinese indigenous breed, is raised for both meat and eggs. According to the tail appearance, the breed is divided into two types referred to “Normal” and “Rumplessness”. The “Normal”type of Hongshan chicken has the normal tail appearance while the “Rumplessness” type is absent of the most or the entire tail feathers. Productive performances of adult "Normal" Hongshan chicken is generally better than the "Rumplessness" type. Since 2003, the two types of Hongshan chicken were both protected by the conservation farm supported by the government in Hubei. However, the genetic foundation of the rumpless phenotype in Hongshan chicken is totally unclear by now. In order to reveal the genetic determination of the trait, we will firstly make a reciprocal cross between the “Normal” and “Rumplessness” types to understand the inheritance of the trait. And then, the chickens of the two types will be sequenced by using whole genome sequencing methods. By using the sequence, we further perform bioinformatics analysis to locate the genes underlying the rumpless trait. In addition, we will do expression and other analysis to understand more about the chicken rumplessness in Hongshan chicken and other rumpless chickens. Our research will unveil the genetic characteristics of rumplessness in Hongshan chicken and will play an important role for the genetic resource.

洪山鸡是我国重要的蛋肉兼用型地方鸡种，根据洪山鸡尾部羽毛的发育情况，可将其分为“翘尾型”和“垂尾型”两个类型。“翘尾型”尾部羽毛完整，与普通鸡种一致，被称为“翘尾型”；“垂尾型”尾部羽毛生长不全，因此成年鸡尾部羽毛呈下垂状，称为“垂尾型”。我国 2003 年开始对这两个类型都进行了保护，但控制洪山鸡尾部性状的分子遗传基础尚不清楚。本研究首先通过家系构建，将“翘尾型”和“垂尾型”的洪山鸡进行杂交，构建资源群体。通过遗传学分析，摸清该尾部性状的遗传规律。通过全基因组测序和生物信息学分析的研究手段，定位并找到影响该性状的相关基因。根据基因定位结果，进而利用表达分析等功能研究技术手段和方法，分析相关基因对洪山鸡垂尾性状形成的遗传作用机理，并在我国其他垂尾鸡种中进行验证，从而阐明鸡垂尾性状的遗传学基础。本项目将深入揭示影响鸡垂尾性状的分子遗传机理，对该品种重要遗传性状的保护、开发和利用具有重要意义。

洪山鸡是湖北省的一个地方鸡种，根据其体型外貌分为翘尾型和垂尾型。本项目对洪山鸡的表型及遗传物质差异均进行了探究。结果表明两种类型洪山鸡体重没有显著性差异，通过X光扫描我们发现垂尾型洪山鸡的尾椎形态及数目都没有变化，这与国外一些品种的垂尾鸡品种不同。而对尾羽外观的比较以及毛囊组织切片的观察，我们认为是羽毛的发育导致了两种类型洪山鸡尾部形状的不同。我们设计了几组杂交实验，通过对后代表型的统计认为垂尾是性连锁的显性性状。本实验选取同一个群体中的24只垂尾母鸡和24只翘尾母鸡，采翅下静脉血液，提取DNA。采用Affymetrix公司的600K芯片进行基因分型，得到与垂尾性状显著相关的几个SNP均位于Z染色体的68.8Mb-68.9Mb (galGal4.0)区域内。该区域位于基因LINGO2中(68,662,670-69,141,063Mb, galGal4.0)。对两种类型洪山鸡进行重测序，计算了一些群体遗传学的指标，最后锁定了Z染色体上71.8-72Mb的区域（galGal5.0）。而在此区域的一个假基因LOC431648很可能是与羽毛发育调节有关的基因。