Association of polymorphisms in the leptin and thyroglobulin genes with meat quality and carcass traits in beef cattle

Abstract

-The objective of the present study was to estimate the allelic and genotypic frequencies of the polymorphisms E2FB (AY138588.1: c.305C> T), located in the leptin gene (LEP), and TG5 (X05380.1:g.-422C>T), located in the thyroglobulin gene (TG), and evaluate the association of these polymorphisms in crossbred cattle of seven distinct genetic groups with the following traits: slaughter weight (SW), hot carcass weight (HCW), hot carcass yield (HCY), carcass fat thickness (CFT), ribeye area (REA), marbling (MARM) and shear force (SF). The animals were genotyped using the PCR-RFLP (Polymorphism Chain Reaction-Restriction Fragment Length Polymorphism) technique, using 201 products obtained from F 1 Caracu × Nellore, Angus × Nellore and Valdostana × Nellore cows, mated to Canchim, Caracu and Red Angus bulls (only Caracu × Nellore cows were used with Red Angus bulls). The allelic and genotypic frequencies were compared using the Chi-squared test. Associations between the genotype of each polymorphism and the traits were analyzed using the General Linear Model (GLM) of statistical software SAS. The least squares means of genotypes of the polymorphisms were compared using Student's t test. The E2FB polymorphism in the LEP gene was associated with CFT, showing the potential for use in national programs for genetic improvement of beef cattle, through the inclusion of SNP in genotyping commercial tests. The TG5 polymorphism in the TG gene was not associated with any of the evaluated traits and was considered ineffective for selection of beef cattle in Brazilian herds.

Genetic diversity analysis of the thyroglobulin gene promoter in buffalo and other bovines

“…The low frequency of the T allele in Indian breeds was in conformity to previous reports in B. indicus (Fortes et al, 2009;Carvalho et al, 2012). However, an in depth analysis of the association of the TG marker in Indian cattle and buffalo is required in order to utilize it for improvement of the meat/milk quality.…”

“…Pannier et al (2010) also did not find any association with marbling and fat deposition traits in various cattle breeds. A lower frequency of the T allele in B. indicus as compared to B. taurus has also been observed previously (Eenennaam et al, 2007;Fortes et al, 2009;Carvalho et al, 2012). Shin and Chung (2007) have reported the association of CC and CT genotypes with a higher marbling score in Korean cattle.…”

Genetic variations in the leptin gene associated with growth and carcass traits in Nellore cattle

“…Considering not only the genotype/environment interaction, but also the existence of epistatic interactions, pleiotropy, genetic linkage, or segregation of other genes that compose the genome is important to display different combinations of the markers described (Carvalho et al, 2012).…”

Genome-wide association study for backfat thickness in Canchim beef cattle using Random Forest approach

“…However, these have had limited success, particularly in response to markers on the DDEF1 and LEP genes [20,23]. Therefore, the identification of genetic markers linked to backfat thickness by novel methodologies is an important strategy for genetic improvement of carcass and meat qualities.…”