Mitogenomics of southern hemisphere blue mussels (Bivalvia: Pteriomorphia): Insights into the evolutionary characteristics of the Mytilus edulis complex

Abstract

Marine blue mussels (Mytilus spp.) are widespread species that exhibit an antitropical distribution with five species occurring in the Northern Hemisphere (M. trossulus, M. edulis, M. galloprovincialis, M. californianus and M. coruscus) and three in the Southern Hemisphere (M. galloprovincialis, M. chilensis and M. platensis). Species limits in this group remain controversial, in particular for those forms that live in South America. Here we investigated structural characteristics of marine mussels mitogenomes, based on published F mtDNA sequences of Northern Hemisphere species and two newly sequenced South American genomes, one from the Atlantic M. platensis and another from the Pacific M. chilensis. These mitogenomes exhibited similar architecture to those of other genomes of Mytilus, including the presence of the Atp8 gene, which is missing in most of the other bivalves. Our evolutionary analysis of mitochondrial genes indicates that purifying selection is the predominant force shaping the evolution of the coding genes. Results of our phylogenetic analyses supported the monophyly of Pteriomorphia and fully resolved the phylogenetic relationships among its five orders. Finally, the low genetic divergence of specimens assigned to M. chilensis and M. platensis suggests that these South American marine mussels represent conspecific variants rather than distinct species.

Comparative Large-Scale Mitogenomics Evidences Clade-Specific Evolutionary Trends in Mitochondrial DNAs of Bivalvia

“…Such a pattern of overall negative selection was already detected for the species of genus Mytilus (Zbawicka et al 2014; Gaitán-Espitia et al 2016). …”

The coastal North Pacific: Origins and history of a dominant marine biota

“…Not all taxa with a disjunct temperate distribution in the north and south temperate Pacific achieved that distribution by long‐distance dispersal in the Pacific, a case in point of the mussel genus Mytilus . Molecular evidence indicates that the temperate South American populations of Mytilus , occurring in both Chile and Argentina, reached the Southern Hemisphere not from the North Pacific, but by way of the North Atlantic, where Mytilus had arrived during the trans‐Arctic interchange following the opening of Bering Strait (Gaitán‐Espitia, Quintero‐Galvis, Mesas, & D'elía, ; Gerard, Bierne, Borsa, Cheneuil, & Feral, ; Hilbish et al., ). In this connection, it is interesting to note that it is the lineage of M. edulis , M. trossulus and M. galloprovincialis that reached the Southern Hemisphere, and not that of M. californianus and M. coruscus , which did not participate in the colonization of the North Atlantic.…”

“…Not all taxa with a disjunct temperate distribution in the north and south temperate Pacific achieved that distribution by long-distance dispersal in the Pacific, a case in point of the mussel genus Gaitán-Espitia, Quintero-Galvis, Mesas, & D'elía, 2016;Gerard, Bierne, Borsa, Cheneuil, & Feral, 2008;Hilbish et al, 2000). In this connection, it is interesting to note that it is the lineage of M. edulis, M. trossulus and M. galloprovincialis that reached the Southern Hemisphere, and not that of M. californianus and M. coruscus, which did not participate in the colonization of the North Atlantic.…”

Native and invasive taxa on the Pacific coast of South America: Impacts on aquaculture, traceability and biodiversity of blue mussels (Mytilus spp.)

“…Although the distributions of these taxa have been studied extensively in the Northern Hemisphere, in the Southern Hemisphere taxon distributions do not always fit the classical “ Mytilus edulis complex” scheme. Whilst we have a better (but still not completely resolved) understanding of the situation in Australia and New Zealand (Ab Rahim et al., ; Gardner et al., ; Westfall and Gardner, , ), the situation in South America still requires resolution (Gaitán‐Espitia, Quintero‐Galvis, Mesas, & D'Elía, ; Oyarzún, Toro, Cañete, & Gardner, ).…”

“…Production is concentrated in the Gulf of Reloncaví and along the coastline of Chiloé Island (Los Lagos region) and is based on the native blue mussel, nominally Mytilus chilensis. However, other species in Chile have also been reported, including M. galloprovincialis in the Gulf of Arauco-Bío-Bío region Daguin & Borsa, 2000;Tarifeño et al, 2012;Westfall & Gardner, 2010) and M. edulis in the Strait of Magellan-Magallanes region (Oyarzún et al, 2016), although this last species is named as M. platensis by Gaitán-Espitia et al (2016). In addition, at a limited number of locations along the Chilean coast, allele characteristics of M. trossulus (but not M. trossulus mussels themselves) have also been reported (Larraín et al, 2012;Oyarzún et al, 2016).…”