Characterization and validation of bovine Gonadotripin releasing hormone receptor (GnRHr) polymorphisms

LIRON J.P.; PRANDO A.J.; RIPOLI M.V.; ROGBERG MUNOZ A.; POSIK D.M.; BALDO A.; PERAL GARCIA P.; GIOVAMBATTISTA G.

Edimburgo

Conferencia; XXXII Conference of the International Society for Animal Genetics; 2010

International Society for Animal Genetics

  Gonadotropin releasing hormone and its receptor (GnRHr) play a critical role in sexual differentiation and reproduction. Available evidence shows a strong genetic component in the timing of puberty. In bovines, there are signifi cant differences within and among beef breeds in the time when bulls reach puberty. Despite its economic importance, there are not many SNPs or genetic markers associated with this characteristic. The aims of the study were to identify DNA polymorphism in the bovine GnRHr by re-sequencing analysis, determine haplotype phases, and perform a population study in a selected tag SNP in 6 breeds. Eight SNPs were detected, including: one in the URR, fi ve in the coding regions, and two in non-coding regions. This polymorphism level corresponds to one variant every 249.4 bp and a global nucleotide diversity of 0.385. Two haplogroups comprising nine haplotypes and two linkage blocks were detected. Despite 5 tag SNPs were required to capture all variability, just one SNP allowed to defi ne both haplogroups, and only two SNPs were needed to differentiate the most common haplotypes. An additional taq SNP was necessary to identify both URR variants. Allele-frequency analysis of a selected taq SNP among breeds showed a geographical cline. European Bos taurus breeds had lower frequencies of the C allele than B. indicus type cattle, while Creole cattle and Wagyu breeds had intermediate frequency. There was a signifi cant correlation between frequency profi le and timing of puberty among the studied breeds, which seems to suggest that genetic variation within bovine GnRHr gene could explain at least part of the reported variability. Bos taurus breeds had lower frequencies of the C allele than B. indicus type cattle, while Creole cattle and Wagyu breeds had intermediate frequency. There was a signifi cant correlation between frequency profi le and timing of puberty among the studied breeds, which seems to suggest that genetic variation within bovine GnRHr gene could explain at least part of the reported variability.