Detection And Analysis Of Fishy Odor Gene And Feathering Gene Of Beijing Fatty Chicken

Beijing Fatty chicken is a famous local breed for its high quality meat and eggs.It is mainly used to produce middle- or high-grade meat and eggs. At present, the selection for Beijing Fatty chicken is based on conventional selection techniques. However, combining with marker-assisted selection, greater and faster genetic progress can be achieved. This study screened the fishy odor gene and the feathering gene in Beijing Fatty chicken with molecular techniques in order to remove this unfavorable gene in the population and establish the auto-sexing strains by feather growing.The major results of this paper are as follows:(1) The A1034T mutation in fishy odor gene was detected in three quality chicken breeds, Beijing Fatty chicken, Wenchang chicken, and Royal chicken. The homozygous mutant genotype (TT) animals were observed in the Beijing Fatty chicken population only.The gene frequency of this mutant allele in these three populations as follows:Wenchang chicken was 0.10±0.039(P﹤0.01); Royal chicken was 0.12±0.041(P﹤0.01); and Beijing Fatty chicken was 0.15±0.018(P﹤0.01),there is no significant difference in the three breeds(P >0.05).(2) In the feather type analysis, the concordance between the phenotypic observation and the molecular detection reached to 97.87%.(3) No significant difference (P>0.05) were found between different feathering-type hens in early body weight and egg weight, while there seemed to exist a trend that early feathering hens were heavier than late feathering hens in body weight. Significant difference (P <0.05) between early feathering hens and late feathering hens in Beijing Fatty chicken was found in second breast index, high-foot index. The day of first egg (DFE) for early feathering hens was one week earlier than that for late feathering hens, so till 44 weeks old, they layied 6 eggs more(P <0.05)than late feathering ones. The effect of the feathering gene on the production performance in Beijing Fatty chicken varied with sex, for the early body weights of cocks with late feathering type were significantly higher than those of cocks with early feathering type(P <0.01).Conclusions of this paper are as follows: (1) Fishy smell-sensitive allele existed in Beijing Fatty chicken, Wenchang chicken and Royal chicken populations,and recessive homozygous individuals were detected in the Beijing Fatty chicken population, so it is necessary to eliminate this unfavorable allele with mark-assisted selction .(2) There existed another single nuclear polymorphism near the published fishy smell-sensitive mutation site in Beijing Fatty chicken. Using a new primer set, it could identify the genotypes of the A1034T locus in FMO3 gene with the PCR-RFLP approach easily and accurately.(3) The gene affecting feathering speed in Beijing Fatty chicken population is also sex-linked, which means that the Beijing Fatty chicken breed has the genetic basis for setting up auto-sexing lines with feathering types.