Nucleotide sequence preservation of human mitochondrial DNA.

Abstract

Recombinant DNA techniques were used to quantitate the amount of nucleotide sequence divergence in the mitochondrial DNA population of individual normal humans. Mitochondrial DNA was isolated from the peripheral blood lymphocytes of 5 normal humans and cloned in M13 mp11; 49 kilobases of nucleotide sequence information was obtained from 248 independently isolated clones from the 5 normal donors. Both between- and within-individual differences were identified. Between-individual differences were identified in .apprxeq. 1/200 nucleotides. Only one within-individual difference was identified in 49 kilobases of nucleotide sequence information. This high degree of mitochondrial nucleotide sequence homogeneity in human somatic cells is in marked contrast to the rapid evolutionary divergence of human mitochondrial DNA and suggests the existence of mechanisms for the concerted preservation of mammalian mitochondrial DNA sequences in single organisms.