鸭的NPY基因克隆和适应性检验分析

Cloning of Gaoyou Duck's NPY Gene and its Adaptive Evolution Test

根据已知的鸭近缘物种及哺乳动物的神经肽Y（Neuropeptide Y,NPY）基因序列设计引物,利用RT-PCR技术从高邮鸭生殖轴组织总RNA中克隆出NPY基因cDNA序列,采用生物信息学方法分析不同物种间序列同源性和进化关系,并利用PAML4b检测位点选择压力。序列分析结果表明,克隆获得的鸭NPY基因cDNA片段序列长度约300bp,其与近缘物种序列的相似性在92%~96%之间,与哺乳动物序列的相似性在77%~84%之间,与鱼类序列的相似性在33%~39%之间。在系统进化树的拓扑结构中,禽类、哺乳动物和鱼类分别位于独立分支,揭示的系统发育关系和物种进化相一致。序列适应性进化检验结果表明,哺乳动物NPY基因在进化过程中经历了正选择作用,而禽类和鱼类NPY基因经历了较强的净化选择作用。研究结果有助于了解NPY基因进化历程及结构与功能变异,为进一步研究其与鸭繁殖性能的关系提供了基础。

The primers were designed according to the NPY gene sequences of mammals or duck＇s congeneric species,then cDNA sequence of NPY gene was cloned from total RNA of tissues in Gaoyou Duck by RT-PCR.Homology and evolution correlation of NPY genes among different species were analyzed by biology infomatic method.PAML4b were used to test the selective pressure of NPY gene.Sequence comparison analysis indicated that the cloned Gaoyou Duck NPY gene cDNA was 300bp in length.The alignment of Gaouyou Duck NPY gene cDNA sequence with those of congeneric species,mammals and fishes showed that the sequence similaries were respectively 92%~96%,77%~84% and 33%~39%.Avians,mammals and fishes were independent in the cladogram topological structure,which was consistent their evolutionary histories.The selection test showed that mammal,s NPY gene had suffered positive selection pressure,however,avian and fish NPY gene had suffered stronger purifying selection.The results could aid to trace the route of NPY gene evolution and knowledge of its structure and function variations.It also laid a foundation for the further study on relations between NPY gene with reproduction performance of Ducks.