Leptin promoter polymorphisms and uses thereof
The present invention relates to single nucleotide polymorphisms (SNPs) in the leptin promoter, and to methods for the identification of animals carrying specific alleles of these SNPs that are associated with circulating leptin levels, feed intake, growth rate, body weight, carcass merit and carcass composition. The present invention provides oligonucleotides that can be used as primers and/or probes to amplify and/or detect these SNPs, and provides methods for selecting and grouping animals, in particular bovines, according to genotype.
1. A method for identifying a bovine animal as having a particular daily dry matter intake, body weight, slaughter weight, or carcass weight phenotype, said method comprising:
(a) obtaining a biological sample from a bovine, said sample comprising nucleic acids from said bovine;
(b) detecting in said nucleic acids the nucleotide content at both alleles of the UASMS1 or UASMS3 polymorphic position in the leptin gene to determine the UASMS1 or UASMS3 genotype of the bovine, wherein the UASMS1 polymorphic position is either a C or a T at position 207 of SEQ ID NO: 1 and the UASMS3 polymorphic position is either a C or a G at position 1759 of SEQ ID NO: 1; and
(c) correlating the UASMS1 or UASMS3 genotype with the daily dry matter intake, body weight, slaughter weight, or carcass weight phenotype of the bovine, wherein:
(i) the presence of a CC UASMS1 genotype or a CC UASMS3 genotype is indicative of lower daily dry matter intake, body weight, slaughter weight, or carcass weight phenotype;
(ii) the presence of a TT UASMS1 genotype or a GG UASMS3 genotype is indicative of higher daily dry matter intake, body weight, slaughter weight, or carcass weight phenotype; and
(iii) the presence of a heterozygous CT UASMS1 genotype or a CG UASMS3 genotype is indicative of a daily dry matter intake, body weight, slaughter weight, or carcass weight phenotype that is intermediate to the level of said phenotypes in animals having a CC UASMS1 genotype, a CC UASMS3 genotype, a TT UASMS1 genotype or a GG UASMS3.
2. A method for selectively breeding bovine animals that have particular daily dry matter intake, body weight, slaughter weight, or carcass weight phenotypes, comprising:
(a) extracting DNA from a tissue or blood sample of bovine animals;
(b) amplifying said DNA with:
(i) a first primer that anneals to the leptin gene promoter at a location upstream of nucleotide position 207 of SEQ ID NO: 1; and a second primer that anneals to the leptin gene promoter at a location downstream of nucleotide position 207 of SEQ ID NO: 1;
(ii) a first primer that anneals to the leptin gene promoter at a location upstream of nucleotide position 1759 of SEQ ID NO: 1; and a second primer that anneals to the leptin gene promoter at a location downstream of nucleotide position 1759 of SEQ ID NO: 1;
(iii) a first primer comprising SEQ ID NO: 7; and a second primer comprising SEQ ID NO: 8; or
(iv) a first primer comprising SEQ ID NO: 15; and a second primer comprising SEQ ID NO: 16;
(c) determining the genotypes of said subject bovine animals at polymorphic position UASMS1 or UASMS3, wherein the UASMS1 polymorphic position is either a C or a T at position 207 of SEQ ID NO: 1 and the UASMS3 polymorphic position is either a C or a G at position 1759 of SEQ ID NO: 1;
(d) grouping individual animals into sub-groups wherein each animal in a sub-group has the same genotype at the position of the UASMS1 or UASMS3 polymorphism; and
(e) selectively breeding animals from particular sub-groups.