title: Association of a missense mutation in the bovine leptin gene with carcass fat content and leptin mRNA levels.
abstract: Previously, we have shown that alleles of the BM1500 microsatellite, located 3.6 kb downstream of the leptin gene in cattle, were associated with carcass fat measures in a population of 154 unrelated beef bulls. Subsequently, a cytosine (C) to thymine (T) transition that encoded an amino acid change of an arginine to a cysteine was identified in exon 2 of the leptin gene. A PCR-RFLP was designed and allele frequencies in four beef breeds were correlated with levels of carcass fat. The T allele was associated with fatter carcasses and the C allele with leaner carcasses. The frequencies of the SNP alleles among breeds indicated that British breeds have a higher frequency of the T allele whereas the continental breeds have a higher occurrence of the C allele. A ribonuclease protection assay was developed to quantify leptin mRNA in a separate group of animals selected by genotype. Animals homozygous for thymine expressed higher levels of leptin mRNA. This may suggest that the T allele, which adds an extra cysteine to the protein, imparts a partial loss of biological function and hence could be the causative mutation.
authors.affiliation: Department of Animal and Poultry Science, 51 Campus Drive, University of Saskatchewan, Saskatoon, S7N 5A8, Canada. buchanan@sask.usask.ca
authors.forename: Fiona C
authors.initials: FC
authors.lastname: Buchanan
authors.forename: Carolyn J
authors.initials: CJ
authors.lastname: Fitzsimmons
authors.forename: Andrew G
authors.initials: AG
authors.lastname: Van Kessel
authors.forename: Tracey D
authors.initials: TD
authors.lastname: Thue
authors.forename: Dianne C
authors.initials: DC
authors.lastname: Winkelman-Sim
authors.forename: Sheila M
authors.initials: SM
authors.lastname: Schmutz
mesh_terms: D000273:Adipose Tissue / Q000254:growth & development; D019943:Amino Acid Substitution; D000818:Animals; D001483:Base Sequence; D001823:Body Composition; D002417:Cattle / Q000235:genetics* / Q000254:growth & development*; D005091:Exons; D005787:Gene Frequency; D005838:Genotype; D006720:Homozygote; D020738:Leptin / Q000096:biosynthesis / Q000235:genetics*; D008297:Male; D018895:Microsatellite Repeats; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D010641:Phenotype; D020641:Polymorphism, Single Nucleotide; D012333:RNA, Messenger / Q000096:biosynthesis
chemical_list: D020738:Leptin; D012333:RNA, Messenger