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MITOCHONDRIAL DNA VARIATION IS ASSOCIATED WITH MEASURABLE DIFFERENCES IN LIFE‐HISTORY TRAITS AND MITOCHONDRIAL METABOLISM IN DROSOPHILA SIMULANS
Author(s) -
Ballard J. William O.,
Melvin Richard G.,
Katewa Subhash D.,
Maas Koen
Publication year - 2007
Publication title -
evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.84
H-Index - 199
eISSN - 1558-5646
pISSN - 0014-3820
DOI - 10.1111/j.1558-5646.2007.00133.x
Subject(s) - biology , mitochondrial dna , nuclear gene , genetics , nonsynonymous substitution , gene , cytochrome c oxidase , mitochondrion , nuclear dna , phenotype , alternative oxidase , evolutionary biology , genome
Recent studies have used a variety of theoretical arguments to show that mitochondrial (mt) DNA rarely evolves as a strictly neutral marker and that selection operates on the mtDNA of many species. However, the vast majority of researchers are not convinced by these arguments because data linking mtDNA variation with phenotypic differences are limited. We investigated sequence variation in the three mtDNA and nine nuclear genes (including all isoforms) that encode the 12 subunits of cytochrome c oxidase of the electron transport chain in Drosophila . We then studied cytochrome c oxidase activity as a key aspect of mitochondrial bioenergetics and four life‐history traits. In Drosophila simulans , sequence data from the three mtDNA encoded cytochrome c oxidase genes show that there are 76 synonymous and two nonsynonymous fixed differences among flies harboring si II compared with si III mtDNA. In contrast, 13 nuclear encoded genes show no evidence of genetic subdivision associated with the mtDNA. Flies with si III mtDNA had higher cytochrome c oxidase activity and were more starvation resistant. Flies harboring si II mtDNA had greater egg size and fecundity, and recovered faster from cold coma. These data are consistent with a causative role for mtDNA variation in these phenotypic differences, but we cannot completely rule out the involvement of nuclear genes. The results of this study have significant implications for the use of mtDNA as an assumed neutral marker and show that evolutionary shifts can involve changes in mtDNA despite the small number of genes encoded in the organelle genome.