Haplotypes at the 5′-Flanking Region of Peroxisome Proliferator-Activated Receptor γ Gene and Their Association with the Growth and Body Composition Traits in Chickens

Peroxisome proliferator-activated receptor γ (PPARγ) is an important regulator of chicken preadipocyte proliferation and differentiation. In this study, polymorphisms were detected by DNA sequencing, PCR-RFLP and some other methods and three polymorphisms (g.-1784_-1768del17, c.-1241G>A and c.-75G>A) were found in the 5′ flanking region of PPARγ gene. Growth and body composition traits were measured in the 8th–10th generation populations of the Northeast Agricultural University broiler lines were divergently selected for abdominal fat content. Polymorphisms among individuals were screened in the above populations. The haplotype-based association analysis on growth and body composition traits was carried out. The association analysis showed that haplotypes based on three polymorphisms at 5′ flanking region of PPARγ gene were significantly associated with abdominal fat weight (AFW), abdominal fat percentage (AFP, AFW/BW7), liver weight (LW), liver weight percentage (LFP, LW/BW7), shank length (ShL), femur weight (FeW), keel length (KeL), and metatarsus circle (MeC) (P<0.05) and suggestive significantly associated with pectoralis major weight (PMaW), pectoralis minor weight (PMiW), pectoralis minor weight percentage (PMiWP, PMiW/BW7), and metatarsus length (MeL) (P<0.2). The least square analysis showed that the birds with BGA haplotype had significantly higher AFW and AFP than the birds with other haplotypes (P<0.05). The birds with AAG haplotype had significantly higher LW and LW/BW than the birds with other haplotypes (P<0.05). The birds with AAG haplotype had significantly higher PMiW and PMiW/BW than the birds with other haplotypes (P<0.05). The birds with AAG haplotype had significantly higher ShL, FeW, MeL, MeC and KeL than the birds with AGG haplotypes (P<0.05). The results in this study revealed that QTL affecting fatness traits may exist in 5′ flanking region of PPARγ gene in chickens and PPARγ gene might be one of the genes having important influences on the growth and bone traits in chickens.