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Insulin- like growth factor 2 ( IGF2) is a potent cell growth and differentiation factor and is implicated in mammals' growth and development. The objective of this study was to evaluate the effects of the mutations in the bovine IGF2 with growth traits in Chinese Qinchuan cattle. Four single nucleotide polymorphisms (SNPs) were detected of the bovine IGF2 by DNA pool sequencing and forced polymerase chain reaction-restriction fragment length polymorphism (forced PCR-RFLP) methods. We also investigated haplotype structure and linkage disequilibrium (LD) coefficients for four SNPs in 817 individuals representing two main cattle breeds from China. The result of haplotype analysis showed eight different haplotypes and 27 combined genotypes within the study population. The statistical analyses indicated that the four SNPs, combined genotypes and haplotypes are associated with the withers height, body length, chest breadth, chest depth and body weight in Qinchuan cattle population ( P < 0.05 or <0.01). The mutant-type variants and mutant haplotype (Hap 8: ATGG; likely to be the beneficial QTN allele) was superior for growth traits; the heterozygote diplotype was associated with higher growth traits compared to wild-type homozygote. Our results provide evidence that polymorphisms in the IGF2 gene are associated with growth traits, and may be used for marker-assisted selection in beef cattle breeding program. [ABSTRACT FROM AUTHOR]

The transcription factor paired box 6 gene ( PAX6) plays a key role during the early development of various organs. In this study, three single nucleotide polymorphisms (SNPs) have been identified in the introns 2, 8 and 11 of the bovine PAX6 gene. 8 haplotypes and 13 diplotypes were revealed and the linkage disequilibrium (LD) was assessed in 817 cows representing four main cattle breeds from China (Nanyang, NY; Qinchuan, QC; Jiaxian, JX; Chinese Holstein, CH). The LD analysis revealed that the additional three SNPs were not in strong LD, the wild haplotype (Hap 1: CTT) and mutant haplotype (Hap 8: TCC) have a frequency of 9.36, 35.61, 18.32, 57.15 % and 15.60, 14.19, 0.83, 0 % in the four cattle populations. The statistical analyses indicated that the SNP2 and 3 are associated with the body weight at birth, 6 and 12 months in NY and JX cattle population ( P < 0.01 or P < 0.05); and significant association was detected between 19 (NY) or 13 (JX) diplotype (combined genotypes) and body weight at different ages (birth, 6 and 12 months). Our results provide evidence that some polymorphisms in PAX6 are associated with growth traits at some ages, and may be used as candidates for marker-assisted selection in beef cattle breeding program. [ABSTRACT FROM AUTHOR]

Adipocyte determination and differentiation-dependent factor 1/sterol regulatory element-binding protein-1c (ADD1/SREBP1c) is a major determinant of tissue differential lipogenic capacity in mammalian and avian species. The objectives of the present study were to focus on insertion-deletion polymorphism (indel) in the bovine ADD1/SREBP1c gene, and analyzing its effect on growth traits in a sample of 1035 cattle belonging to four Chinese cattle breeds. PCR-SSCP, DNA sequencing and agarose electrophoresis methods were used. The 778 bp PCR products of ADD1/SREBP1c gene exhibited three genotypes and two alleles were revealed: W and D. Frequencies of the W allele varied from 0.8651 to 1.000. The associations of the 84 bp indel mutation of ADD1/SREBP1c gene with growth traits of 265 Nanyang cows were analyzed. The animals with genotype WD had significantly higher birth weight, body weight, average daily gain than those with genotype WW at birth, 6-, 12-, 18-, and 24-month old (P < 0.05 or P < 0.01). These results suggest that the indel mutation of bovine ADD1/SREBP1c gene may influence the growth traits in cattle.