Premium
Relaxed selection on male mitochondrial genes in DUI bivalves eases the need for mitonuclear coevolution
Author(s) -
Maeda Gerald P.,
Iannello Mariangela,
McConie Hunter J.,
Ghiselli Fabrizio,
Havird Justin C.
Publication year - 2021
Publication title -
journal of evolutionary biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.289
H-Index - 128
eISSN - 1420-9101
pISSN - 1010-061X
DOI - 10.1111/jeb.13931
Subject(s) - biology , genome , nuclear gene , coevolution , mitochondrial dna , gene , genetics , evolutionary biology , negative selection , selection (genetic algorithm) , artificial intelligence , computer science
Mitonuclear coevolution is an important prerequisite for efficient energy production in eukaryotes. However, many bivalve taxa experience doubly uniparental inheritance (DUI) and have sex‐specific mitochondrial (mt) genomes, providing a challenge for mitonuclear coevolution. We examined possible mechanisms to reconcile mitonuclear coevolution with DUI. No nuclear‐encoded, sex‐specific OXPHOS paralogs were found in the DUI clam Ruditapes philippinarum , refuting OXPHOS paralogy as a solution in this species. It is also unlikely that mt changes causing disruption of nuclear interactions are strongly selected against because sex‐specific mt‐residues or those under positive selection in M mt genes were not depleted for contacting nuclear‐encoded residues. However, M genomes showed consistently higher d N / d S ratios compared to putatively ancestral F genomes in all mt OXPHOS genes and across all DUI species. Further analyses indicated that this was consistently due to relaxed, not positive selection on M vs. F mt OXPHOS genes. Similarly, selection was relaxed on the F genome of DUI species compared to species with strict maternal inheritance. Coupled with recent physiological and molecular evolution studies, we suggest that relaxed selection on M mt function limits the need to maintain mitonuclear interactions in M genomes compared to F genomes. We discuss our findings with regard to OXPHOS function and the origin of DUI.