Mitochondrial DNA evolution in the Montium-species subgroup of Drosophila

Mitochondrial DNA (mtDNA) restriction-site maps for six species (10strains) of the Drosophila montium subgroup were established. A total of 50restriction sites were mapped, corresponding to 1.67% of the mtDNA genome.On the basis of differences in the restriction sites, nucleotide divergence(delta) was calculated for each pair of species (strains), and phylogenetictrees were constructed by using distance- matrix and parsimony methods.Comparison of the resultant phylogenetic trees shows that the siblingspecies D. auraria and D. quadraria are closely related. At the otherextreme, considerable divergence was observed between the two strains of D.serrata and between D. serrata and D. birchii, a finding that contrastswith their grouping within the same species complex. Nevertheless, our dataindicate that these six oriental montium species are rather closelyrelated.