title: Polymorphisms within the Telomerase Reverse Transcriptase gene (TERT) in four breeds of dogs selected for difference in lifespan and cancer susceptibility.
abstract: BACKGROUND
  Enzymatic activity of Telomerase Reverse Transcriptase (TERT) is important in maintaining the telomere length and has been implicated in cancer and aging related pathology. Since cancer susceptibility as well as longevity of dogs vary between breeds, this study involved sequencing the entire TERT gene of Canis familiaris from DNA samples obtained from forty dogs, with ten dogs each of four breeds: Shih Tzu, Dachshund, Irish Wolfhound, and Newfoundland, each with different life expectancies and susceptibility to cancer.
  
  
  RESULTS
  We compared the sequences of all forty individuals amongst one another and with the published sequence of canine TERT, and analyzed relationships between members of the same or different breeds. Two separate phylogenetic trees were generated and analyzed from these individuals. Polymorphisms were found most frequently in intronic regions of the gene, although exonic polymorphisms also were observed. In many locations genotypes were observed that were either homozygous for the reference sequence or heterozygous, but the variant homozygous genotype was not observed.
  
  
  CONCLUSIONS
  We propose that these homozygous variants are likely to have adverse effects in dogs. It was also found that the polymorphisms did not segregate by breed. Because the four breeds chosen come from geographically and physiologically distinct backgrounds, it can be inferred that the polymorphic diversification of TERT preceded breed derivation.
authors.forename: Camille A
authors.initials: CA
authors.lastname: McAloney
authors.forename: Kevin A T
authors.initials: KA
authors.lastname: Silverstein
authors.forename: Jaime F
authors.initials: JF
authors.lastname: Modiano
authors.affiliation: Masonic Cancer Center, University of Minnesota, Minneapolis, MN 55455, USA. bach005@umn.edu.
authors.forename: Anindya
authors.initials: A
authors.lastname: Bagchi
mesh_terms: D000818:Animals; D004283:Dog Diseases / Q000235:genetics*; D004285:Dogs / Q000235:genetics*; D015971:Gene Expression Regulation, Enzymologic; D020022:Genetic Predisposition to Disease; D008136:Longevity / Q000235:genetics*; D009369:Neoplasms / Q000235:genetics / Q000662:veterinary*; D011110:Polymorphism, Genetic / Q000502:physiology*; D019098:Telomerase / Q000235:genetics / Q000378:metabolism*
chemical_list: D019098:Telomerase