Nucleotide sequence preservation of human leukemic mitochondrial DNA.

Nucleotide sequence variation in mitochondrial DNA isolated from human leukemic cells has been analyzed by recombinant DNA techniques. Three hundred eighty-seven independent recombinant DNA clones, each containing one of three defined segments of mitochondrial DNA isolated from the neoplastic cells of four leukemic patients, were analyzed. Partial nucleotide sequence determination of the 387 clones yielded a total of 81.7 kilobases of nucleotide sequence information. The only evidence of within-individual nucleotide sequence divergence consisted of three clones containing deletions of one or two nucleotides in one mitochondrial DNA region. These clones were three of 113 independent clones isolated from a patient with acute lymphocytic leukemia. The low level of nucleotide sequence divergence in the mitochondrial DNA population of neoplastic cells from individual leukemic patients suggests that a mechanism or mechanisms exist that limit the development of nucleotide sequence divergence in mammalian mitochondrial DNA. The results further suggest that this mechanism does not appear to be abrogated by neoplastic transformation in leukemic patients.