Novel 61-bp Indel of RIN2 Is Associated With Fat and Hatching Weight Traits in Chickens

The Ras and Rab interactor 2 (RIN2) gene, which encodes RAS and Rab interacting protein 2, can interact with GTP-bound Rab5 and participate in early endocytosis. This study found a 61-bp insertion/deletion (indel) in the RIN2 intron region, and 3 genotypes II, ID, and DD were observed. Genotype analysis of mutation sites was performed on 665 individuals from F(2) population and 8 chicken breeds. It was found that the indel existed in each breed and that yellow feathered chickens were mainly of the DD genotype. Correlation analysis of growth and carcass traits in the F(2) population of Xinghua and White Recessive Rock chickens showed that the 61-bp indel was significantly correlated with abdominal fat weight, abdominal fat rate, fat width, and hatching weight (P < 0.05). RIN2 mRNA was expressed in all the tested tissues, and its expression in abdominal fat was higher than that in other tissues. In addition, the expression of the RIN2 mRNA in the abdominal fat of the DD genotype was significantly higher than that of the II genotype (P < 0.05). The transcriptional activity results showed that the luciferase activity of the pGL3-DD vector was significantly higher than that of the pGL3-II vector (P < 0.01). Moreover, the results indicate that the polymorphisms in transcription factor binding sites (TFBSs) of 61-bp indel may affect the transcriptional activity of RIN2, and thus alter fat traits in chicken. The results of this study showed that the 61-bp indel was closely related to abdominal fat-related and hatching weight traits of chickens, which may have reference value for molecular marker-assisted selection of chickens.