Genetic Characteristics Of PRL And PRLR Genes And Association With Egg Production Performance In Wanjiang White Goose

Prolactin (PRL) secreted from anterior pituitary plays extensive roles inreproduction, growth, and immunology in animal. In avian, PRL is especiallycrucial for reproduction traits such as broodiness and thus for egg production. PRLcombining its receptor (Prolactin Receptor, PRLR) has effect on target cell with thehelp of PRLR to promote target gene to expression. Mutations in PRL andProlactin receptor gene (PRLR) will bring reproductive disorder. Our research teamhas been committed to develop a new line for more than twenty years. Wanjiangwhite geese, the progeny of the two-line hybridization of the Wanxi Goose andSichuan Goose. However, its fertility is unstable at present, thus the productivity islimited. To elect the molecular genetic markers related to egg performance ofWanjiang white goose, and set up core group, PRL and PRLR genes were selectedas candidates to screen the nueleotide variation by PCR-SSCP method andinvestigate the association of polymorphisms with egg reproduction.In PRL intron2,5genotypes were found: AA, AB, BC, CC and DDgenotypes. More than30SNPs were found in the PCR products. Statistical resultsshow that the polymorphism of the five genotypes is significantly related to the eggproductivity. The differences of egg-laying level between BC and AA, AB, CC,DD genotypes are extremely significant (P<0.01). AA and AB genotypic geeseyield more eggs than BC and DD genotypes. It could be used as a molecularmarker for selecting high-productivity geese.The results also revealed that polymorphisms were discovered in the PCRproducts amplified in PRLR exon10, three genotypes were found: AA, AB and AC.The sequence of AB genotype is the same as original sequence (DQ660982) inNCBI. There are5mutations in AA genotype: Câ†'A at840bp, Câ†'T at862bp,Tâ†'C at875bp, Tâ†'A at963bp, Aâ†'T at989bp, resulting in amino acid mutations: Hisâ†'Asn, Thrâ†'Ile, Asnâ†'Lys, Thrâ†'Ser, and synonymous mutation at875bp. Sequencing revealed5mutations in AC genotype: Gâ†'T at816bp, Aâ†'Tat861bp, Câ†'T at862bp, Tâ†'C at875bp, Aâ†'G at948bp, causing amino acidmutations of Valâ†'Phe, Thrâ†'Phe, synonymous mutations at875bp and963bp.Besides, there are an N-glycosylation site (NQSR),3casein kinase â…¡phosphorylation sites including SIIE, SKTE, and SLMD in AA genotype;3caseinkinase â…¡ phosphorylation sites including SIIE, SKTE, and TLMD in ABgenotype;3casein kinase â…¡ phosphorylation sites including SIFE, SKTE, andTLMD in AC genotype. The annual egg yielding of AB genotype geese aresignificantly more than those of AA and AC genotype geese on the average(P<0.05). It is suggested for the first time that PRLR is a promising candidate genethat can affect egg performance in Wanjiang white goose.The achievements of the study stands great significance for the acceleration ofpoultry breeding progress against broodiness to enhance egg production andbreeding ability, and allow us to beter utilize local avian genetic resources, andtherefore, have a broad perspective for application.