NATURALLY OCCURRING MITOCHONDRIAL DNA HAPLOTYPES EXHIBIT METABOLIC DIFFERENCES: INSIGHT INTO FUNCTIONAL PROPERTIES OF MITOCHONDRIA

Authors

  • Nicolas Pichaud,

    1. Laboratoire de biologie intégrative, Département de Biologie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, Québec, Canada G5L 3A1
    2. E-mail: n.pichaud@unsw.edu.au
    3. School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
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  • J. William O. Ballard,

    1. School of Biotechnology and Biomolecular Sciences, University of New South Wales, Sydney, New South Wales 2052, Australia
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  • Robert M. Tanguay,

    1. Laboratoire de Génétique Cellulaire et développementale, Département de Biologie Moléculaire, Biochimie Médicale et Pathologie, Institut de Biologie intégrative et des systèmes, 1030 ave de la Médecine, Université Laval, Québec, Canada G1V 0A6
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  • Pierre U. Blier

    1. Laboratoire de biologie intégrative, Département de Biologie, Université du Québec à Rimouski, 300 Allée des Ursulines, Rimouski, Québec, Canada G5L 3A1
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Abstract

Linking the mitochondrial genotype and the organismal phenotype is of paramount importance in evolution of mitochondria. In this study, we determined the differences in catalytic properties of mitochondria dictated by divergences in the siII and siIII haplogroups of Drosophila simulans using introgressions of siII mtDNA type into the siIII nuclear background. We used a novel in situ method (permeabilized fibers) that allowed us to accurately measure the consumption of oxygen by mitochondria in constructed siII-introgressed flies and in siIII-control flies. Our results showed that the catalytic capacity of the electron transport system is not impaired by introgressions, suggesting that the functional properties of mitochondria are tightly related to the mtDNA haplogroup and not to the nuclear DNA or to the mito-nuclear interactions. This is the first study, to our knowledge, that demonstrates a naturally occurring haplogroup can confer specific functional differences in aspects of mitochondrial metabolism. This study illustrates the importance of mtDNA changes on organelle evolution and highlights the potential bioenergetic and metabolic impacts that divergent mitochondrial haplogroups may have upon a wide variety of species including humans.

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