Polymorphisms and haplotypes in the bovine neuropeptide Y, growth hormone receptor, ghrelin, insulin-like growth factor 2, and uncoupling proteins 2 and 3 genes and their associations with measures of growth, performance, feed efficiency, and carcass merit in beef cattle1

Abstract

Genes that regulate metabolism and energy partitioning have the potential to influence economically important traits in farm animals, as do polymorphisms within these genes. In the current study, SNP in the bovine neuropeptide Y (NPY), growth hormone receptor (GHR), ghrelin (GHRL), uncoupling proteins 2 and 3 (UCP2 and UCP3), IGF2, corticotrophin-releasing hormone (CRH), cocaine and amphetamine regulated transcript (CART), melanocortin-4 receptor (MC4R), proopiomelanocortin (POMC), and GH genes were evaluated for associations with growth, feed efficiency, and carcass merit in beef steers. In total, 24 SNP were evaluated for associations with these traits and haplotypes were constructed within each gene when 2 or more SNP showed significant associations. An A/G SNP located in intron 4 of the GHR gene had the largest effects on BW of the animals (dominance effect P < 0.01) and feed efficiency (allele substitution effect P < 0.05). Another A/G SNP located in the promoter region of GHR had similar effects but the haplotypes of these 2 SNP reduced the effects of the SNP located in intron 4. Three SNP in the NPY gene showed associations to marbling (P < 0.001) as well as with ADG, BW, and feed conversion ratio (FCR; P < 0.05). The combination of these 3 SNP into haplotypes generally improved the association or had a similar scale of association as each single SNP. Only 1 SNP in UCP3, an A/G SNP in intron 3, was associated with ADG (P = 0.025), partial efficiency of growth, and FCR (P < 0.01). Three SNP in UCP2 gene were in almost complete linkage disequilibrium and showed associations with lean meat yield, yield grade, DMI, and BW (P < 0.05). Haplo-types between the SNP in UCP3 and UCP2 generally reduced the associations seen individually in each SNP. An A/G SNP in the GHRL gene tended to show effects on residual feed intake, FCR, and partial efficiency of growth (P < 0.10). The IGF2 SNP most strongly affected LM area (P < 0.01), back fat, ADG, and FCR (P < 0.05). The SNP in the CART, MC4R, POMC, GH, and CRH genes did not show associations at P < 0.05 with any of the traits. Although most of the SNP that showed associations do not cause amino acid changes, these SNP could be linked to other yet to be detected causative mutations or nearby QTL. It will be very important to verify these results in other cattle populations.

Prospecting candidate SNPs for backfat in Canchim beef cattle

“…Some genes, such as leptin (Stone et al, 1996) on BTA4 and thyroglobulin on BTA14 (Barendse et al, 2001), have been indicated as candidates that can influence these traits, although some of the results are conflicting (Buchanan et al, 2002;Casas et al, 2005;Rincker et al, 2006;Gan et al, 2008;Sherman et al, 2008).…”

An association of C/T polymorphism in exon 2 of the bovine insulin-like growth factor 2 gene with meat production traits in Polish Holstein-Friesian cattle

“…This polymorphism was associated with the rib-eye area and the carcass fat per cent in beef cattle (Godall and Schmutz, 2007). In another study, the g.292C>T polymorphism strongly affected LM (musculus longissimus dorsi) area, backfat, average daily gain, and feed conversion ratio (Sherman et al, 2008). Zhao et al (2002) found a T/G transversion (RFLP-AciI) in exon 9 of the IGF2 gene in Angus cattle; the GG genotype animals tended to have higher body weight and daily weight gain.…”

Genetic polymorphisms of the IGF-II gene intron 8 coding region and its association with growth and carcass traits in yak

“…Furthermore, CC genotype bulls had a significantly higher mean carcass fat content than those with CT and TT genotypes. Sherman et al (2008) found that the g.292C>T polymorphism significantly affected several traits related to meat production in a synthetic line of beef cattle. In steers, the allele substitution effect on final body weight was 6.67 kg, in which TT animals were 17.66 kg heavier than those with the CC genotype, and were 5.71 kg heavier than CT animals.…”

“…This polymorphism was later associated with rib-eye area (REA) and carcass fat percentage in beef cattle (Goodall and Schmutz, 2007). In another study, a g.292C>T polymorphism was found to strongly affect the longissimus dorsi muscle area, back fat, average daily weight gain (ADG), and feed conversion ratio (Sherman et al, 2008). Zhao et al (2002) found a T/G transversion (RFLP-AciI) in exon 9 of the IGF-II gene in Angus cattle, in which animals with the GG genotype tended to have higher body weights and ADG.…”