Determination of the relationship between class IV sirtuin genes and growth traits in Chinese black Tibetan sheep.

Class IV sirtuin ( SIRT6 and SIRT7 ) played essential roles in biometabolism processes via deacetylating specific transcription factors. The present study was conducted to search for mutations in SIRT6 / 7 and determine their associations with growth traits in black Tibetan sheep. Via DNA sequencing methods, three single-nucleotide polymorphisms (SNPs) were identified in 427 ewes, including a mutation (g.3724C > T) in the intron 1 of SIRT6 and two mutations (g.3668G > T and g.4223C > G) in SIRT7 intron 6 and 8, respectively. Based on the χ 2 test, both g.3724C > T and g.4223C > G loci fitted with Hardy-Weinberg equilibrium ( p  > 0.05). Compared with animals with genotype TT, the CC genotype at g.3724C > T locus ( SIRT6 ) exhibited the highest mean for body weight ( p  < 0.05) and heart girth ( p  < 0.05). At g.3668G > T locus ( SIRT7 ), individuals carrying the GG genotype tended to have heavier body weight than those of TT genotype ( p  < 0.05). With the exception of body weight, body measurement traits not affected by combinative genotype ( p  > 0.05). Our results could be used as genetic markers for marker-assisted selection and maybe guide sheep breeding in economic traits.