Abstract
Canine gastroenteritis with its significant high morbidity, mortality and financial burden represents one of the most prevalent illnesses affecting dogs globally. The individual host genetic structure and immunity related genes diversity influence the vulnerability to different inflammatory reactions including gastrointestinal infections. This study focuses on examining the DNA sequence variations in the Toll-like receptor 4 (TLR4) and interleukin-6 (IL-6) genes in Baladi dogs suffering from gastroenteritis. Blood samples were collected from twenty dogs categorized as; ten dogs with gastroenteritis and another ten clinically free from gastroenteritis or any gastro disease. First step; was extracting their genomic DNA then portions of the TLR4 (311 bp) and IL-6 (630 bp) genes were amplified by PCR and then DNA sequencing done by Sanger sequence. The outcome sequences were compared after that by the reference sequences received from GenBank in order to find nucleotide differences and detect any polymorphisms. PCR amplified the targeted regions 630 bp and 311 bp, for the IL-6 and TLR4 genes respectively. A A105G single nucleotide polymorphism (SNP) in eight healthy dogs was revealed from the sequence analysis of IL-6 that proves the presence of a genetic variation in the studied population. This detected polymorphism was validated through comparison to the reference sequence. On the other hand, sequencing of the amplified TLR4 segment showed a monomorphic pattern in infected dogs with gastroenteritis and healthy group, this indicates strong sequence conservation in the examined area. So the results show genetic heterogeneity in the IL-6 gene represented in SNP while the examined TLR4 fragment remained substantially conserved in Baladi dogs. These findings show that IL-6 gene could be a more indicative candidate gene than TLR4 gene when a genetic variation examination is needed for canine gastroenteritis indication.

Key words: Gene polymorphism, Dogs, Gastroenteritis incidence, IL-6 gene, TLR4 gene