催乳素受体基因与羊驼繁殖性能关系的初探

A Study on the Relationship between Prolactin Receptor Gene and Reproductive Capability of Alpaca (Lama pacos)

通过氯仿/异戊醇法制备羊驼血液基因组DNA,采用PCR方法首次扩增出羊驼催乳素受体基因(prolactin receptor gene,PRLR)exon8-exon9序列(GenBank登录号为DQ198164),该片段长度为622bp。通过NCBI blast(http://www.ncbi.nlm.nih.gov/BLAST/)比较,结果表明:该序列包括exon8的82bp、intron8全序列472bp和exon9的68bp。同源性比较发现,羊驼PRLR基因exon8和exon9核苷酸序列与其它哺乳动物的相应区域的同源性特高,均≥92%;同时还发现羊驼exon8引物后第19个碱基为G,而其它哺乳动物(猪除外)均为A,猪则是在羊驼exon8引物后的第34个碱基处由G变为A,通过推导氨基酸序列分析发现,这种单碱基的突变使得羊驼与其它哺乳动物相比,该处的氨基酸由亮氨酸取代了异亮氨酸;在羊驼exon9引物前第22个碱基处也发生了A-G碱基替换现象,但这个碱基的突变发生在密码子的第3个碱基上,编码的氨基酸均为脯氨酸。在这些动物中只有羊驼为单胎动物,羊驼exon8核苷酸序列中A-G的碱基替换并引起编码氨基酸序列发生改变是否与羊驼繁殖性能有关还有待进一步研究。

In order to study the relationship of prolactin receptor gene（PRLR） with reproduction capability of alpacas, and to analyze the homology to other mammals, blood samples from 60 Huacaya alpacas, breed in China Alpacas Base, were taken and their genomic DNAs were extracted by the method of hydroxybenzene / chloroform. The primers were designed to amplify exon8-exon9 of PRLR fragment of alpaca. Sequencing results showed that the fragment covered 622 bp （GenBank accession No. DQ198164） , which included partial sequence of exon8 （82 bp） , intron8 （472 bp） and partial exon9 （68 bp）. And the alignments of the sequence with the corresponding part of other animals （ such as cow, sheep, pig, dog, rabbit, rat and so on） was performed, and revealed that the homology of exon8 and exon9 of alpacas PRLR gene was above 92 %. Meanwhile, a single base mutation was detected in the nucleotide of PRLR gene of alpacas, which were G→A at the position of 19 after sense primer, and it lead to amino acid substitution of I→L; and another mutation was at the position of 22 before anti-sense primer, but which located the third base of codon and coding P amino acid. Alpacas are single embryo animals, if the mutation of amino acid is related to the reproduction capability of alpacas is needed to study further.