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Role‐reversal of gender‐associated mitochondrial DNA affects mitochondrial function in Mytilus edulis (Bivalvia: Mytilidae)
Author(s) -
Breton Sophie,
Stewart Donald T.,
Blier Pierre U.
Publication year - 2008
Publication title -
journal of experimental zoology part b: molecular and developmental evolution
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.823
H-Index - 63
eISSN - 1552-5015
pISSN - 1552-5007
DOI - 10.1002/jez.b.20251
Subject(s) - mitochondrial dna , biology , heteroplasmy , genetics , mytilus , mytilidae , genome , gene , zoology , mollusca , bivalvia , ecology
Mussel species of the genus Mytilus possess an unusual system of mitochondrial DNA (mtDNA) transmission termed doubly uniparental inheritance. They are characterized by the presence of two highly divergent gender‐associated mtDNA genomes (often with>20 and>10% divergences in DNA and amino acid sequences, respectively) that are inherited either maternally (F mtDNA) or paternally (M mtDNA). Females are typically homoplasmic for the F mtDNA and males are heteroplasmic with the F mtDNA being most common in all tissues except the gonad that is dominated by the M mtDNA. Collectively, males are polymorphic for two classes of M mtDNAs known as the “standard male” and “recently masculinized” M types (SM and RM, respectively). The coding portions of the RM mtDNA genome differ from the SM mtDNA by as much as the maternally inherited F mtDNA genome differs from the SM type. Because the SM and RM types exhibit considerable amino acid sequence divergence, we hypothesized that these differences could affect mitochondrial respiratory chain complex enzyme activities. To test this hypothesis, the activity of the major mitochondrial respiratory chain complexes (complexes II, I+III and IV) as well as the activity of citrate synthase were measured on gonad samples from males containing either the SM or RM mtDNA. Our data demonstrate that the mitochondrial subunits encoded by the RM mtDNA are associated with higher enzymatic activities than the gene products of the SM mtDNA. J. Exp. Zool. (Mol. Dev. Evol.) 312B:108–117, 2009 . © 2008 Wiley‐Liss, Inc.