mtDNA analysis in Portuguese populations (Central Portugal and Azores Islands): polymorphic sites in control region sequences

Abstract

Background: The polymorphism of the two hypervariable segments (HVI and HVII) of the control region of mtDNA was analyzed in a population of 81 unrelated individuals from Central Portugal and 48 from the Azores Islands, using a fluorescent-based electrophoresis sequencing method. Methods: Sequences have been obtained with ABI PRISM0 Big Dye Terminator and dRhodamine Terminator Cycle Sequencing Ready Reaction Kits, with Amplitaq DNA Polymerase FS, and have been detected with ABI PRISM 377 DNA sequencer. Results: In the Central Portugal population (n=81), we observed 69 polymorphic sites of sequence in HVI region and 44 in HVII region. In the Azores population (n=48), we observed 48 polymorphic sites of sequence in HVI region and 24 in HVII region. Conclusions: Nucleotide substitution rather than insertion/deletion (1 or 2 bp) was the majority of variation. The distribution showed a large bias towards transitional changes than transversional changes. Our sequencing results are similar to other Caucasian population data.