Dubious maternal inheritance of mitochondrial DNA inD. simulansand evolution ofD. mauritiana

Abstract

Summary: Within-line heterogeneity has been found in the mitochondrial DNA (mtDNA) in two isofemale lines ofD. simulans. The co-existing types, S and M, were typical of the mtDNA inD. simulansand inD. mauritiana, respectively, their nucleotide divergence per site beingca.2·1%. Segregation analysis confirmed that some individuals in these lines were heteroplasmic and suggested incomplete maternal inheritance of mtDNA inDrosophila. Examination of other lines ofD. simulansrevealed that the M type ofD. mauritianaoccurs at 71% in Réunion, 38% in Madagascar and 0% in Kenya. This finding and interspecific sequence comparisons of both M types indicate thatD. mauritianadiverged fromD. simulansprobably less than 240000 years ago.