The complete male-type mitochondrial genomes of the Fatmucket, Lampsilis siliquoidea, and the endangered Arkansas Fatmucket, Lampsilis powellii

Abstract

Doubly uniparental inheritance (DUI) is a unique mode of mitochondrial (mt) inheritance found only in some bivalve molluscs. Under DUI, both maternal (i.e. female-transmitted or F-type) and paternal (i.e. male-transmitted or M-type) mitochondrial genomes are transmitted. In addition to typical mt genes, these F- and M-type genomes each contain a distinct novel open reading frame, termed the f- and m-orf, respectively. Herein, the M-type mitochondrial genomes of Lampsilis siliquoidea and Lampsilis powellii (two putative unionid species within Unionidae) are presented. Relatively few M-type mitochondrial genomes have been sequenced. Consequently, these results are valuable for the on-going study of patterns of molecular evolution of DUI genomes. Both a phylogenetic analysis and an in silico analysis of the novel ORFs were conducted. Consistent with previous studies of unionoid M-type genomes, our results demonstrate the presence of a putative transmembrane domain in these M-ORFs with properties similar to those of M-ORFs of closely related species.