Polymorphisms Of Bovine ADRB3, CAPN3, CAPN4 Genes And Their Effects On Growth And Carcass Traits

In this study, the variation of ADRB3 gene was detected in Chinese cattle, Tianzhu white yak, Gannan yak, Qinghai yak, and ten cattle breeds in New Zealand including Hereford, Shorthorn, Angus, Murray Grey, Simmental, South Devon, Charolais, Red Poll, Highland and Salers by PCR-SSCP, as well as the CAPN3 and CAPN4 genes in some of above populations, in order to understand the genetic characters of these three genes in cattle and yak. Based on the pivotal role of ADRB3 in lipolytic and thermogenic processes in mammal and potential effects on growth and carcass traits of domestic animal, the association of the polymorphisms in 3′-UTR of ADRB3 gene and Estimated Breeding Values (EBVs) of growth and carcass traits were analyzed for the purpose of evaluating the possibility of ADRB3 as a candidate gene for growth and carcass traits in the investigated cattle breeds. The main results showed as follows:1. Polymorphisms of ADRB3, CAPN3 and CAPN4 genesSix PCR-SSCP patterns representing six alleles A-F containing four single nucleotide polymorphisms (SNPs) and three nucleotide deletion/insertions were observed at the promoter region of ADRB3 gene in 737 cattle from ten breeds in New Zealand and one Chinese cattle population by PCR-SSCP. Allele A was the most common allele with frequency of more than 86% in ten cattle populations excluding Highand, especially all of Salers represented genotype AA. Alleles distributed disproportionably among eleven populations, such as allele C observed in Charolais and allele F in Hereford and Murray Grey, as well as alleles D and E only in Chinese cattle. The promoter region of ADRB3 gene showed low genetic diversity with polymorphism information content (PIC) of less than 0.25 in all of the populations except Highland cattle with PIC of 0.3666. Those results suggested that strong selection pressure were applied to cattle in both New Zealand and China to maintain low genetic diversity at promoter region of ADRB3 gene.Two alleles YA and YB were checked at promoter region of ADRB3 gene in 334 individuals from three yak populations in China. There were three SNPs within allele YB relative to allele YA in yak or allele A in cattle. Mutation of c.-430A>T that particularly detected within allele YB showed genetic characteristic of ADRB3 in yak as distingushed from cattle. Allele YB was the most common allele with frequency of 97.3% and 98.0% in Tianzh white yak and Qinghai yak respectively, but there was only identified allele YB in Gannan yak. It was possible that allele YA came from cattle because of very low frequency in yak and same sequence with allele A of cattle. The polymorphism at promoter region of ADRB3 in yak was low with PIC less than 0.25, considering the association of ADRB3 gene with cold tolerance of mammal, suggesting strong selection pressure is being applied to yak by cold climate in alpine region to maintain low genetic diversity at this locus in the population.Four alleles A, B,C and D were identified at 3′-UTR of ADRB3 gene in total 1142 cattle from seven breeds including Angus, Shorthorn, Hereford, Simmental, Murray Grey, Red Poll and South Devon. Alleles B, C and D contained five SNPs relative to allele A. Allele A was the most common allele according to frequency ranged from 63.63%-93.73% in all investigated population except Shorthorn with frequency of alleles A and B of 35.90% and 41.76%, respectively. Four alleles distributed unequally among seven populations, and alleles A and B were detected in all populations and alleles C in Simmental, Hereford and Shorthorn, but allele D not in Murray Grey as well. According to PIC at 3′-UTR of ADRB3, polymorphism was poor in Murray Grey and Red Poll with PIC of less than 0.25 and moderate in Angus and Hereford and South Devon with PIC ranged from 0.25 to 0.5, and higher in Simmental and Shorthorn with PIC morn than 0.5.No variation was detected at exon 1 of CAPN3 gene in Highland, Red Poll, Hereford, Angus and Simmental cattle from New Zealand, but two alleles A and B were observed in Chinese cattle and allele A was the most common allele with frequency of 96.98%. The mutation of c.54T>G detected at allele B resulted in a non-synonymous substitution of p.Met18Arg polymorphism relative to allele A. Genetic diversity was poor at the exon 1 of CAPN3 gene in Chinese cattle with PIC of 0.0568.No mutation was checked in exon 5-6 of CAPN4 in Salers cattle and Gannan yak, but two alleles A and B were found in Chinese cattle and allele A was the most common allele with a frequency of 96.14%. There was a substitution of c.411+24G>C detected at intron 5 in allele B relative to allele A. The exon 5-6 of CAPN4 in Chinese cattle showed low polymorphism with PIC of 0.0568.2. Effects of polymorphisms in 3′-UTR of ADRB3 gene on EBVs of some growth and carcass traits in cattle.Variations at the 3′-UTR of ADRB3 gene was not found to have a significant effect on birth weight EBV of investigated cattle breeds.Genotypes of ADRB3 were found to have a significant effect on 600-day and mature cow weight EBV of Hereford cattle (P<0.05) and Least significant difference revealed the individuals with genotype AB was higher (P<0.05 or P<0.01) than that with AC. The presence of allele A had a significantly negative effect on mature cow weight EBV (P<0.01), as well as the presence of allele C on 200-day weight EBV (P<0.05), 600-day weight EBV (P<0.01) and carcass weight EBV (P<0.01), respectively. Selection of the individuals with genotype AB would increase the 600-day weight and mature cow weight of their progenies.EBVs of growth and carcass traits were not significantly different between individuals with different genotypes of ADRB3 in Shorthorn. The presence of allele B had a significantly negative effects on 200-day weight EBV (P<0.01) and 600-day weight EBV (P<0.05), whereas the allele D had a significantly positive effect on mature cow weight EBV (P<0.05). As a result, 200-day and 600-day weight of progenies would increase by reducing the frequency of allele B in Shorthorn cattle, and the mature cow weight of progenies would be put on with adding the frequency of allele D as well.The individuals with genotype BB of ADRB3 was higher than that with AA (P<0.05 or P<0.01) in 400-day, 600-day, mature cow and carcass weight EBV of Angus cattle, while that with AB was found between the two. The presence of allele A had a significantly negative effects on 600-day and mature cow weight EBV (P<0.05) and carcass weight EBV (P<0.01), but the presence of allele B had a significantly positive effect on 400-day weight EBV. Considering the very low frequency of genotype BB suggesting a strong selection pressure being applied to individuals with that genotype in Angus, the selective reaction of other traits associated with ADRB3 gene need to be evaluated carefully as improvement of the growth and carcass traits by adding individuals with genotype BB in Angus cattle.Genotype of ADRB3 was not found to affect 200-day and 400-day weight EBV in Murray Grey cattle investigated. But individuals with genotype AB was higher in 600-day weight EBV than that with AA (P<0.05). Therefore, selection of individuals with genotype AB would increase 600-day weight of their progenies.Genotype and allelic presence of ADRB3 gene were not found to have significant effects on 200-day, 400-day and 600-day weight EBVs in South Devon cattle investigated.There were no significantly different in 200- to 600-day weight EBV among genotype of ADRB3 in Simmental cattle investigated. But presence of allele B had a significantly negative effect on 400-day and 600-day weight EBV (P<0.05).In summary, ADRB3, CAPN3 and CAPN4 gene appear to play a pivotal role in regulation of lipolytic and thermogenic in adipose tissue of mammal and proteolytic processes in muscles, respectively, thus those genes could be involved in bovine growth and carcass qualities. In this study we reported identification of novel mutations at the promoter region and 3′-UTR of ADRB3, exon 1 of CAPN3 and intron 5 of CAPN4 representing the genetic characteristics of three genes in cattle or yak populations investigated. The particular SNP at promoter region of ADRB3 in yak would contribute to molecular research for stronger cold tolerance of yak than cattle. It also provided a basis for Molecular Marker-assisted Selection (MAS) that the variations at 3′-UTR of ADRB3 showed different effects on EBVs of growth and carcass traits in investigated cattle breeds.