Demographic history of a recent invasion of house mice on the isolated Island of Gough

Abstract

Island populations provide natural laboratories for studying key contributors to evolutionary change, including natural selection, population size, and the colonization of new environments. The demographic histories of island populations can be reconstructed from patterns of genetic diversity. House mice (Mus musculus) inhabit islands throughout the globe, making them an attractive system for studying island colonization from a genetic perspective. Gough Island, in the central South Atlantic Ocean, is one of the remotest islands in the world. House mice were introduced to Gough Island by sealers during the 19th century, and display unusual phenotypes, including exceptionally large body size and carnivorous feeding behavior. We describe genetic variation in Gough Island mice using mitochondrial sequences, nuclear sequences, and microsatellites. Phylogenetic analysis of mitochondrial sequences suggested that Gough Island mice belong to Mus musculus domesticus, with the maternal lineage possibly originating in England or France. Cluster analyses of microsatellites revealed genetic membership for Gough Island mice in multiple coastal populations in Western Europe, suggesting admixed ancestry. Gough Island mice showed substantial reductions in mitochondrial and nuclear sequence variation and weak reductions in microsatellite diversity compared with Western European populations, consistent with a population bottleneck. Approximate Bayesian Computation (ABC) estimated that mice recently colonized Gough Island (~100 years ago) and experienced a 98% reduction in population size followed by a rapid expansion. Our results indicate that the unusual phenotypes of Gough Island mice evolved rapidly, positioning these mice as useful models for understanding rapid phenotypic evolution.

Genetics of Rapid and Extreme Size Evolution in Island Mice

“…Gough Island mice belong to the same subspecies as the laboratory mouse (Mus musculus domesticus) (Gray et al 2014), providing access to an expansive genetic toolkit for investigating their phenotypic evolution. In this article, we focus on the rapid evolution of body size, for two reasons.…”

“…Gough Island mice weigh approximately twice as much as their mainland relatives (Jones et al 2003). Mice were introduced to Gough Island by teams of seal hunters (Wace 1961;Jones et al 2003) between 130 and 200 years ago (Verrill 1895;Gray et al 2014), suggesting that body size evolution has been very rapid.Gough Island mice belong to the same subspecies as the laboratory mouse (Mus musculus domesticus) (Gray et al 2014), providing access to an expansive genetic toolkit for investigating their phenotypic evolution. In this article, we focus on the rapid evolution of body size, for two reasons.…”

“…Gough Island mice weigh approximately twice as much as their mainland relatives (Jones et al 2003). Mice were introduced to Gough Island by teams of seal hunters (Wace 1961;Jones et al 2003) between 130 and 200 years ago (Verrill 1895;Gray et al 2014), suggesting that body size evolution has been very rapid.…”

The ghost of introduction past: Spatial and temporal variability in the genetic diversity of invasive smallmouth bass

“…Furthermore, the presence of a temporal Wahlund effect within the HN range, likely due to the pooling of multiple populations, may too have decreased the accuracy of the ABC results. Although our results support the notion of multiple introductions, this should be interpreted with caution as several factors may be responsible for this pattern, including an unsampled source population, postinvasion genetic drift, insufficient marker resolution and admixture in the source population (Chown et al., 2015; Gray et al., 2014). Given that hatcheries make use of artificial selection techniques to enhance species production and abundance (e.g., Aprahamian, Smith, McGinnity, McKelvey, & Taylor, 2003; Lamaze et al., 2012), it is possible that the introduced M. dolomieu were of admixed or hybrid origin, as has been reported for stockings of S. fontinalis (Cooper, Miller, & Kapuscinski, 2010; Lamaze et al., 2012; Sloss, Jennings, Franckowiak, & Pratt, 2008).…”

“…These types of studies aid in unravelling the demographic history of the invasive species in question (Ficetola, Bonin, & Miaud, 2008; Gillis, Walters, Fernandes, & Hoffman, 2009; Gray et al., 2014; Neilson & Stepien, 2011). Yet, despite the wealth of specimens and information housed within Natural History collections, the majority of invasion studies to date have focussed exclusively on contemporary populations, thereby relying heavily on the premise that the historic population structure within the native range has been maintained over time.…”