Rat mitochondrial DNA polymorphism: sequence analysis of a hypervariable site for insertions/deletions

• Published in: Nucleic Acids Research
• Main Authors: Brown, Gregory G., DesRosiers, Lee J.
• Format: Text
• Language: English
• Published: Oxford University Press 1983
• Subjects: MOLECULAR BIOLOGY; Rattus rattus
• Online Access: http://nar.oxfordjournals.org/cgi/content/short/11/19/6699; https://doi.org/10.1093/nar/11.19.6699

Three closely related variants of rat ( Rattus norvegicus ) mtDNA have been shown to differ in the number of T residues found in a run of Ts (light strand) which spans the junction between the tRNACys and tRNATyr genes. The number of Ts in the repeat varies from 6 to 8 in these DNAs. Another, less closely related, R. norvegicus variant has a run of 5 Ts at this site and in the related species, Rattus rattus , a run of 4 Ts is found. In R. norvegicus mtDNA runs of 5 As and 5 Gs are found just to the 3' side of the variable T repeat, and it is suggested that the three runs of repeated nucleotides may stabilize heteroduplexes which result from strand slippage and which give rise to the insertions and/or deletions. Among 17 mtDNA clones derived from an individual with the 8T repeat, one clone was found which possessed a 9T repeat. This variant may represent an additional DNA type originally present within the individual.