Detection of key gene InDels in TGF-? pathway and its relationship with growth traits in four sheep breeds

TGF-? signaling pathway plays an important role in regulating cell proliferation and differentiation, embryonic development, bone formation, etc. LTBP1, THBS1, SMAD4 and other genes are important members of TGF-? signaling pathway. LTBP1 binds to TGF-?, while THBS1 binds to LTBP1, which is an important signal transduction molecule in the TGF-? pathway. In order to explore the effects of the insertion/deletion variation of three genes (LTBP1, THBS1, SMAD4) in the TGF-? signaling pathway on the growth traits such as body length and body weight of sheep, a total of 625 healthy individuals from 4 breeds of the Tong sheep, Hu sheep, small-tail Han sheep and Lanzhou fat-tail sheep were identified and analyzed. In this study, we identified 4 InDel loci: one loci of LTBP1, two loci of THBS1, and one loci of SMAD4, respectively named as: InDel-1 (deletion 13?bp), InDel-2 (deletion 16?bp), InDel-3 (deletion 22?bp), InDel-4 (deletion 7?bp). Among the 4 analyzed breeds, association analysis showed that all new InDel polymorphisms were significantly associated with 10 different growth traits (p?<?0.05), which may provide a theoretical basis for sheep breeding to accelerate the progression of marker-assisted selection in sheep breeding.