Variation frequency and base composition characterization types of human mitochondrial DNA control region

Objective To explore the variation frequency and base composition characterization of mitochondrial DNA (mtDNA) control region in human beings. Methods Eighty-six sequences of human mtDNA D-loop region from GenBank were collected and compared with Cambridge sequence. Results A total of 1 253 variations in 181 sites were found in 86 sequences. The dominant type of variation was nucleotide transition (71.75%), followed by insertion (16.04%) and deletion (8.62%). The nucleotide transversion only accounted for 3.59%. The nucleotide sites 16、189,303-315,and 514-523 were the ones with high variation frequency and length instability. Conclusion The mitochondrial control region is a hypervariable area with high frequency of polymorphism. The evaluation of variation frequency in this region provides a good reference for the studies aiming at the relationship between mitochondrial DNA polymorphism and pathogenetic risk of diseases.