鸡无尾性状的分子机制研究进展

动物的尾巴具有改变方向、控制升降、调整速度、支撑身体、防御、攻击、保温、示警、逃生和捕食等作用。鸟类的尾巴在飞行过程中起到平衡身体的关键作用,但在进化过程中尾部却出现了缩短和融合现象,如中国的瓢鸡及智利的Araucana鸡。作者简述了近年来关于鸡无尾性状的解剖学研究成果,发现无尾鸡在胚胎发育HH19期（Hamburger和Humilton标准分期）就已经出现无尾现象,而在结构上无尾鸡缺乏尾脂腺、尾羽、镰羽、尾椎骨和尾综骨。同时作者分析了导致尾部体节停止发育的分子遗传机制,包括周期性表达基因的转录调控影响尾部延伸过程、后端化因子梯度诱导尾部形成、Hox基因影响体节特化过程及基因突变有可能导致的无尾现象等,从而提出了可能导致家禽无尾性状的胚胎发育时期的关键分子及信号通路,包括Irx1和Irx2基因、Notch信号通路、Wnt信号通路、Fgf信号通路、RA信号通路等。研究鸡无尾性状的分子机制不仅可深入了解脊椎动物胚胎发育中尾部发育机制,更有利于揭示鸟类在进化过程中发生的尾部缩短及融合的机理。

Research Progress on Molecular Mechanisms of Rumpless Trait in Chicken

The tail of an animal has the functions of direction changing,movement and speed controlling,body supporting,defense,attack,heat preservation,warning, escape and predation.The tail of birds plays a key role in maintaining balance during flight,but in evolution,the tail appears to shorten and fuse,such as Piao chicken in China and Araucana chicken in Chile. The authors reviewed the anatomy research about rumpless characters of chicken in recent years,the results showed that there had been shown rumples phenomenon in the period of Hamburger and Humilton 19 stage,and rumpless chicken were lack of uropygial gland,rectrix,sickle feather, caudal vertebra and pygostyle. At the same time,the author analyzed the molecular genetic mechanism of caudal vertebrae development arrest,including the transcriptional regulation of the periodic expression genes that influenced the tail extension process, the back-end factors gradient induces tail formation, the Hox gene influenced the process of segmental specialization,and gene mutation that might lead to rumpless phenomenon. The author proposed the key molecular and signaling pathways in embryonic development,including Irx1 and Irx2 genes,Notch signaling pathway,Wnt signaling pathway,Fgf signaling pathway and RA signaling pathway. The study of the molecular mechanism of rumpless chicken not only could understand the mechanism of tail development of vertebrate in embryo development, but also helped to reveal the evolution process of tail shortening and fusion in birds.