Studies On Cloning Of PRL Gene Coding Region And Polymorphic Analysis In Wanxi-White Geese

PRL which secreted from anterior pituitary gland has extremely broad spectrum of biological role.PRL mainly related to reproduction in avian species. Increased concentration of Prolactin plays a role inthe cessation of egg laying and broodiness during the active period of lay. Stubborn broodiness of localavian species mainly attributes to their low egg production. In general , PRL was regarded as one of thefactor in intriguing broodiness. As a fine mid-bodied species, Wanxi-White goose has the characters of large body, growth fast atearly time, strong disease resistance, bear coarse feed and high meat quality. Especially, with high downproduction and quality, Wanxi-White goose was well known internationally. However, seasonal egglaying and high broodiness strongly inhibit its egg production. In this study, PRL gene which related tobroodiness was selected as candidate gene. By genome comparison, 7 pair of primers was designedusing Primer Premier5.0 and DnaStar programme in cloning the whole PRL coding region ofWanxi-White goose. PCR-SSCP method along with fragment sequencing was used on testing genemutation at exon1,2 and 5 site. Correlation between mutation in PRL gene and egg production wasanalyzed. Meanwhile, sequencing of PRL coding region and mutation detection at gene coding was alsoanalyzed on Rhine goose to make comparison with Wanxi-White goose. The complete PRL coding region of Wanxi-White goose and Rhine goose was cloned (GenBankaccession number: DQ062571, DQ066733) by the method of Genomic comparison. Homologic analysissuggested that the homology of Wanxi-White goose PRL coding region with Rhine PRL coding regionwas 99%, and 94%, 88% with chicken and duck PRL coding region respectively. Polymorphisms of exon 1, 2 and 5 on Wanxi-White geese and Rhine geese were analyzed. Theresults showed that, no polymorphic site was detected at exon1 amplified fragment, SNPs were detectedat exon 2 and 5 fragment amplified by P3 and P6 prime respectively. C196T mutation in Wanxi-Whitegoose PRL gene resulted to Met67Leu amino acid change, while T492C was a synonymous mutation.C170T mutation in Rhine goose PRL gene resulted to His57Arg amino acid change and T501C was asynonymous mutation. A same T/C mutation was also detected in intron 2 of Wanxi-White goose andRhine goose PRL gene. A T/C mutation was detected at the same site at intron2 in Wanxi-White geeseand Rhine geese PRL gene. Genetic analysis suggested that, among Wanxi-White goose populationm, two allele frequenciesdetected by P3 primer were 0.4237 and 0.5763 respectively, allele frequencies detected by P6 were0.9618 and 0.0328 respectively. In Rhine goose population, allele frequecies detected by P3 and P6were 0.9125, 0.0875 and 0.575, 0.425 respectively. Polymorphic information content (PIC) ofpolymorphic sites in Wanxi- White goose population detected by P3 and P6 primers were 0.3721 and0.0708 respectively. χ~2 fitness test suggest that the population were in the state of Hardy-Weinbergdisequilibrium at the two site. PIC of polymorphic sites in Rhine goose population detected by P3 andP6 primers were 0.1469 and 0.3493 respectively, showed that the population was in the state ofHardy-Weinberg equilibrium at the two sites. In Wanxi-White geese population with egg production records, three genotype frequency at exon2were 0.3282, 0.1908 and 0.4810 with corresponding egg production 19.74±3.69, 20.43±4.13 and21.24±3.82 respectively. Least square analysis showed that genotypes detected by P3 primer had nosignificant relation with egg production. Further reserch is needed on whether polymorphism detected atexon5 has relation with egg production. The total egg production of 43 Rhine geese was 1460 with the mean egg production of 33.95,which had a significant difference with the mean egg production of Wanxi-White geese(20.58) by t test.