Intra-specific sequence variability of tumor necrosis factor-alpha gene (TNFá) in domestic horse breeds.

FRANCISCO E.I.; KALEMKERIAN P B; LIRóN J. P.; GIOVAMBATTISTA G.; ECHEVERRíA M.G.; PERAL GARCíA P.; DíAZ, S.

Amsterdam, Holanda

Conferencia; XXXI Conference of the International Society for Animal Genetics,; 2008

ISAG

Tumour Necrosis Factor alpha (TNFá) is a cytokine that plays a fundamental role in inflammation and immune responses. In horses the coding sequence of TNFá has been mapped within the MHC Class III region in chromosome 20, and SNPs in the promoter region have been previously reported in equine breeds and species. In order to preliminarily investigate the genetic variation within the TNFá gene in domestic horses, we analyse the genomic full-length sequences in fourteen animals from four horse breeds (Argentine Creole, Arab, Spanish Pure Breed and Argentine Silla). Oligonucleotide primers were designed based on the reported TNF horse genomic sequence, to amplify by PCR four overlapping fragments comprising ~2.6 kb within the gene. Each PCR product was sequenced, analyzed and the TNF full-length sequence assembled on each animal by using the algorithms of the Vector NTI and DNAMAN programs. A total of nine SNPs were observed, seven of them located in non-coding regions and two in coding regions. In addition, inter-specific variability was observed when compared to TNF reported sequences from other mammalian species; this variability corresponds to the presence of horse specific amino-acid motifs. Further studies are needed in order to investigate the functional specificity of those motifs and the significance of the observed intra- and inter-specific polymorphisms both in gene expression levels as in susceptibility to various horse diseases.