Divergent evolutionary processes associated with colonization of offshore islands

Abstract

Oceanic islands have been a test ground for evolutionary theory, but here, we focus on the possibilities for evolutionary study created by offshore islands. These can be colonized through various means and by a wide range of species, including those with low dispersal capabilities. We use morphology, modern and ancient sequences of cytochrome b (cytb) and microsatellite genotypes to examine colonization history and evolutionary change associated with occupation of the Orkney archipelago by the common vole (Microtus arvalis), a species found in continental Europe but not in Britain. Among possible colonization scenarios, our results are most consistent with human introduction at least 5100 bp (confirmed by radiocarbon dating). We used approximate Bayesian computation of population history to infer the coast of Belgium as the possible source and estimated the evolutionary timescale using a Bayesian coalescent approach. We showed substantial morphological divergence of the island populations, including a size increase presumably driven by selection and reduced microsatellite variation likely reflecting founder events and genetic drift. More surprisingly, our results suggest that a recent and widespread cytb replacement event in the continental source area purged cytb variation there, whereas the ancestral diversity is largely retained in the colonized islands as a genetic ‘ark’. The replacement event in the continental M. arvalis was probably triggered by anthropogenic causes (land‐use change). Our studies illustrate that small offshore islands can act as field laboratories for studying various evolutionary processes over relatively short timescales, informing about the mainland source area as well as the island.

Exploring the complexity of domestication: a response to Rowley-Conwy and Zeder

“…GMM is becoming a powerful tool for studying prehistoric animal domestication, commensalism and geographic dispersal. The methods have already been employed on a range of species such as pigs (Cucchi, Fujita, and Dobney 2009;Cucchi et al 2011, forthcoming;Krause-Kyora et al 2013;Ottoni et al 2013;Evin et al , 2014Larson, Cucchi, et al 2007), horses (Seetah et al 2014), house mice (Cucchi et al 2013; Valenzuela-Lamas, Baylac, Cucchi, and Vigne 2011) and common voles (Martínková et al 2013).…”

Genetic diversity and colony structure of Tapinoma melanocephalum on the islands and mainland of South China

“…Geographic isolation of invasive species from the mainland results in experiencing different environmental conditions, food resources, and biological competitors and predators. In addition, the water surrounding islands acts as a geographic barrier to dispersal that limits gene flow both between island populations and between island and mainland populations (Barnett et al., 2013; Duffie, Glenn, Vargas, & Parker, 2009). Previous bottlenecks or continued isolation from the mainland can also decrease genetic diversity of invasive species in islands (Losos & Ricklefs, 2009b; Pimm, Diamond, Reed, Russell, & Verner, 1993).…”

Contrasting and congruent patterns of genetic structuring in two Microtus vole species using museum specimens

“…The hybrid zone between them occurs in central European Russia (Meyer et al 1997;Haynes et al 2003;Jaarola et al 2004;Bulatova et al 2010aBulatova et al , b, 2013. For the arvalis form, six main mtDNA lineages have been described in Europe: Western-South, Western-North, Central, Italian, Eastern and Balkan (Haynes et al 2003;Tougard et al 2008;Bužan et al 2010;Martínková et al 2013;Stojak et al 2015). For the field vole, three main evolutionary units (which may represent cryptic species) have been described-Portuguese, Southern and Northern (Paupério et al 2012).…”