[Short repeats and variability in the smooth noncoding area of human mitochondrial DNA].

Major non-coding region of human mitochondrial DNA (mtDNA) (1122 bp) was assessed using the method of complexity analysis of genomes. The ACT, TCA, AGT and TGA motifs (AST-repeats) were shown to form short repeats as well as more complex block structures. These motifs are intrinsic for regulatory sequences of DNA of procaryotic and eucaryotic genes. ACT-repeats based blocks happen to be the most variable parts of the region studied too. Each inherited type of mtDNA is proposed to be a pattern of short repeats arranged with the regard to their symmetry, complementarity and alternativeness thus forming block DNA structures. The existence of similar structures may be possible due to the variability of nucleotide sequences more pronounced in the blocks of repeats of major non-coding region of human mtDNA.