ABSTRAUIr Human mitochondrial DNA was obtained from peripheral blood platelets donated by the members of several independent families. The samples were screened for nucleotide sequence polymorphisms between individuals within these families. In each family in which we were able to detect a distinctly different restriction endonuclease cleavage pattern between the parents, the progeny exhibited the maternal cleavage pattern. Informative

Hypersuppressiveness is a heritable property of some p-mutants (called HS)

The mtDNAs of 235 individuals from five ethnic groups were analyzed for restriction site variation by digestion with restriction endonuclease Hpa I, Southern transfer, and hybridization with 32P-labeled human mtDNA. Six different cleavage patterns (morphs) were found, all of which could be related to each other by single nucleotide substitutions. Differences were found in the frequency of these morphs among the populations.

No abstract

The nucleotide sequence of the mitochondrial DNA (mtDNA) in the region coding for the 3' end of the large rRNA has been determined for two human cell lines bearing independent cytoplasmic chloramphenicol-resistant (CAP-r) mutations. Comparison of the sequences of these two phenotypically different CAP-r mutants with their CAP-sensitive (CAP-s) parental cell lines has revealed a single base change for each in a region which is highly conserved among species. One CAP-r mutation is associated with an A to G transition on the coding strand while the second contains a G to T transversion 52 nucleotides away. Comparable sequence changes in this region had previously been found for mouse and yeast cell mitochondrial CAP-r mutants. Thus, changes in the large rRNA gene eliminate the inhibition of the ribosome by CAP and different nucleotide changes may result in variations in the drug-r phenotype.