Hybridization increases mitochondrial production of reactive oxygen species in sunfish

Du, S. N.N., Khajali, F., Dawson, N. J. and Scott, G. R. (2017) Hybridization increases mitochondrial production of reactive oxygen species in sunfish. Evolution, 71(6), pp. 1643-1652. (doi: 10.1111/evo.13254) (PMID:28444733)

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Mitochondrial dysfunction and oxidative stress have been suggested to be possible mechanisms underlying hybrid breakdown, as a result of mito-nuclear incompatibilities in respiratory complexes of the electron transport system. However, it remains unclear whether hybridization increases the production of reactive oxygen species (ROS) by mitochondria. We used high-resolution respirometry and fluorometry on isolated liver mitochondria to examine mitochondrial physiology and ROS emission in naturally occurring hybrids of pumpkinseed (Lepomis gibbosus) and bluegill (L. macrochirus). ROS emission was greater in hybrids than in both parent species when respiration was supported by complex I (but not complex II) substrates, and was associated with increases in lipid peroxidation. However, respiratory capacities for oxidative phosphorylation, phosphorylation efficiency, and O2 kinetics in hybrids were intermediate between those in parental species. Flux control ratios of capacities for electron transport (measured in uncoupled mitochondria) relative to oxidative phosphorylation suggested that the limiting influence of the phosphorylation system is reduced in hybrids. This likely helped offset impairments in electron transport capacity and complex III activity, but contributed to augmenting ROS production. Therefore, hybridization can increase mitochondrial ROS production, in support of previous suggestions that mitochondrial dysfunction can induce oxidative stress and thus contribute to hybrid breakdown.

Item Type:Articles
Glasgow Author(s) Enlighten ID:Dawson, Dr Neal
Authors: Du, S. N.N., Khajali, F., Dawson, N. J., and Scott, G. R.
College/School:College of Medical Veterinary and Life Sciences > School of Biodiversity, One Health & Veterinary Medicine
Journal Name:Evolution
ISSN (Online):1558-5646
Published Online:19 May 2017
Data DOI:10.5061/dryad.3g16k

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