Open AccessExpanding the Search for Sperm Transmission Elements in the Mitochondrial Genomes of Bivalve Mollusks
Author(s) -
Donald T. Stewart,
Brent M. Robicheau,
Noor Youssef,
Manuel A. Garrido-Ramos,
Emily Chase,
Sophie Breton
Publication year - 2021
Publication title -
genes
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.337
H-Index - 51
ISSN - 2073-4425
DOI - 10.3390/genes12081211
Subject(s) - biology , mitochondrial dna , mytilus , evolutionary biology , genome , non mendelian inheritance , genetics , zoology , ecology , gene
Doubly uniparental inheritance (DUI) of mitochondrial DNA (mtDNA) in bivalve mollusks is one of the most notable departures from the paradigm of strict maternal inheritance of mtDNA among metazoans. Recently, work on the Mediterranean mussel Mytilus galloprovincialis suggested that a nucleotide motif in the control region of this species, known as the sperm transmission element (STE), helps protect male-transmitted mitochondria from destruction during spermatogenesis. Subsequent studies found similar, yet divergent, STE motifs in other marine mussels. Here, we extend the in silico search for mtDNA signatures resembling known STEs. This search is carried out for the large unassigned regions of 157 complete mitochondrial genomes from within the Mytiloida, Veneroida, Unionoida, and Ostreoida bivalve orders. Based on a sliding window approach, we present evidence that there are additional putative STE signatures in the large unassigned regions of several marine clams and freshwater mussels with DUI. We discuss the implications of this finding for interpreting the origin of doubly uniparental inheritance in ancestral bivalve mollusks, as well as potential future in vitro and in silico studies that could further refine our understanding of the early evolution of this unusual system of mtDNA inheritance.