Genetic diversity and connectivity within Mytilus spp. in the subarctic and Arctic

Abstract

Climate changes in the Arctic are predicted to alter distributions of marine species. However, such changes are difficult to quantify because information on present species distribution and the genetic variation within species is lacking or poorly examined. Blue mussels, Mytilus spp., are ecosystem engineers in the coastal zone globally. To improve knowledge of distribution and genetic structure of the Mytilus edulis complex in the Arctic, we analyzed 81 SNPs in 534 Mytilus spp. individuals sampled at 13 sites to provide baseline data for distribution and genetic variation of Mytilus mussels in the European Arctic. Mytilus edulis was the most abundant species found with a clear genetic split between populations in Greenland and the Eastern Atlantic. Surprisingly, analyses revealed the presence of Mytilus trossulus in high Arctic NW Greenland (77°N) and Mytilus galloprovincialis or their hybrids in SW Greenland, Svalbard, and the Pechora Sea. Furthermore, a high degree of hybridization and introgression between species was observed. Our study highlights the importance of distinguishing between congener species, which can display local adaptation and suggests that information on dispersal routes and barriers is essential for accurate predictions of regional susceptibility to range expansions or invasions of boreal species in the Arctic.

Rising air temperatures will increase intertidal mussel abundance in the Arctic

“…Foundation species include shell-forming molluscs as they create hard substrates increasing the abundance of a diverse associated fauna (Gutiérrez et al 2011, Thyrring et al 2015b. In west Greenland, M. edulis and M. trossulus (hereafter referred to as Mytilus) are 2 common foundation species that both form mussel beds, hereby providing microhabitats and food for a diverse associated fauna (Mathiesen et al 2017).…”

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

“…What has been missing until recently is nuclear DNA markers that are speciesspecific and that can resolve ancestry when hybridization occurs either naturally or as a result of anthropogenic transfer of mussel types to non-native regions. Recent advances in next-generation sequencing methods, along with the increase in sequence data deposited in public databases, now permit the development of genomewide single nucleotide polymorphism markers (SNPs) that may be applied in mussel studies to resolve many of these issues because they cover multiple regions of the genome (Araneda et al, 2016;Mathiesen et al, 2017;Saarman & Pogson, 2015;Zbawicka et al, 2012;Zbawicka, Sanko et al, 2014. Blue mussels have long been farmed in many regions of the world (Kijewski, Wijsman, Hummel, & Wenne, 2009;Molinet et al, 2015).…”

Replicated anthropogenic hybridisations reveal parallel patterns of admixture in marine mussels

“…M. galloprovincialis and North-Eu. M. edulis (Figure 1b), and are defined as non-indigenous (Mathiesen et al, 2016). LOF and GAS do not differ significantly at any of the four different ancestry estimates (Table S10).…”

“…M. galloprovincialis lineages. In particular, we used previously extracted DNA from the following studies: (i) Mathiesen et al (2016) who studied the genetics of Mytilus spp. in the sub-Arctic and Arctic using 81 randomly ascertained SNPs.…”

“…Wherever Mytilus species are native, M. galloprovincialis has been shown to be highly competitive and has often displaced local mussels (James T. Carlton, Geller, Reaka-Kudla, & Norse, 1999). M. galloprovincialis has also been reported in the subarctic and Arctic, notably in Norway (Brooks & Farmen, 2013;Mathiesen et al, 2016). Given the low divergence between Atl.…”