Genetic Characteristics Of Smad9Gene And Association With Egg Production Performance In Wanjiang White Goose

Smad family, including at least nine SMAD proteins, named SMAD1~9.SMAD family proteins play important roles in the process of the TGF-β(transforming growth factorβ) signal from the cell surface receptor to the nucleus.Meanwhile, the different SMAD proteins mediated different the TGF-βsignaltransductions， which play important roles in the process of follicular selection ingoose. Wanjiang white geese, the progeny of the two-line hybridization of theWanxi Goose and Sichuan Goose. However, its fertility is unstable at present, thusthe productivity is limited.In this study, mRNA differential display was adopted to investigate genemRNA expression profiling in the follicular development of goose. For the firsttime, a novel SMAD family protein SMAD9(EST CJ111007) was found to beinvolved in follicular initiation and used to be a candidate gene. Functional regionsanalysis of SMAD9indicated that SMAD9protein is highly conserved in MH1andMH2domains, and the connection area is highly variable region.6pairs of primers(p1-p6) were designed to detect the SNPs of Smad9by PCR-SSCP method, andSNPs were found in exon1and intron2amplified with p1and3. Polymorphism and5genotypes (FK, FF, JJ, JK, KK) were found in exon1including2SNPs:243G→A，309T→G，the mutations did not result in amino acid mutations;3genotypes (AA, BB and AB) and1SNP（C→T）in intron2. The annual egg yield ofFK genotype geese or allele gene A in intron2are significantly more than those ofother genotypes on the average (p<0.05). Taken together, it is suggested thatSmad9is a promising candidate gene affecting egg performance in goose.The achievements of the study stand great significance for the acceleration ofpoultry breeding progress against broodiness to enhance egg production andbreeding ability, and allow us to better utilize local avian genetic resources, andtherefore, have a broad perspective for application.