A molecular characterization of the charismatic Faroe house mouse

Abstract

Faroe house mice are a 'classic' system of rapid and dramatic morphological divergence highlighted by J. S. Huxley during the development of the Modern Synthesis. In the present study, we characterize these charismatic mice using modern molecular techniques, examining specimens from all Faroe islands occupied by mice. The aims were to classify the mice within the modern house mouse taxonomy (i.e. as either Mus musculus domesticus or Mus musculus musculus) using four molecular markers and a morphological feature, and to examine the genetic diversity and possible routes of colonization using mitochondrial (mt) control region DNA sequences and microsatellite data (15 loci). Mice on the most remote islands were characterized as M. m. domesticus and exhibited exceptionally low genetic diversity, whereas those on better connected islands were more genetically diverse and had both M. m. musculus and M. m. domesticus genetic elements, including one population which was morphologically M. m. musculus-like. The mtDNA data indicate that the majority of the mice had their origins in south-western Norway (or possibly southern Denmark/northern Germany), and probably arrived with the Vikings, earlier than suggested by Huxley. The M. m. musculus genetic component appears to derive from recent mouse immigration from Denmark.

Experimental island invasion of house mice

“…Multiple invasion events and ongoing gene-flow are known to increase genetic diversity (Jones et al 2011;Gabriel et al 2013) and the independent incursion of an additional female mouse during our experiment suggests this is not an uncommon event for supplementing population genetic diversity. Ongoing introduction of new propagules plays an important role in successful invasions.…”

“…We expected to find signals of drastically reduced genetic diversity in the invading population compared to the incumbent one due to founder effects. Notwithstanding, other studies have documented persistence of house mouse populations for centuries despite low genetic diversity and population bottlenecks (Jones et al 2011;Hardouin et al 2010). We therefore predicted that low genetic diversity would have no effect on the demographics of the invading population in the short term.…”

Deconstructing Mus gemischus: advances in understanding ancestry, structure, and variation in the genome of the laboratory mouse

“…This evolutionary history provides the context for why M. musculus became a favorite model to address broad scientific questions, including (1) genetics of adaptation, due to the rapidity and extent of its dispersal and the readiness with which it has flourished in a diverse array of environments (Gabriel et al 2010; Hardouin et al 2010); (2) speciation, due to the ongoing divergence of the three subspecies and their secondary contact at several hybrid zones around the world (Mihola et al 2009); and (3) as a means of tracking the historical movements of human populations (Gabriel et al 2010, 2011; Jones et al 2011, 2012). In addition, the house mouse is an agricultural pest and a vector for disease, and there is ongoing research focused on combating its economic and public health impact (Brown and Singleton 2002; Meerburg et al 2009; Stenseth et al 2003).…”

Coevolution of Cryptosporidium tyzzeri and the house mouse (Mus musculus)

“…Another subspecies, Mus musculus domesticus (Mmd), expanded westward through Asia Minor to southern and western Europe and northern Africa, and later has spread worldwide (Boursot et al, 1993; Guénet and Bonhomme, 2003; Rajabi-Maham et al, 2008; Duvaux et al, 2011; Auffray and Britton-Davidian, 2012; Bonhomme and Searle, 2012; Cucchi et al, 2012). In the area of their secondary contact in Europe, the two subspecies have formed a hybrid zone over 2,500 km long, stretching from Norway to the Black Sea (Macholán et al, 2003; Jones et al, 2011; Ďureje et al, 2012). Due to the colonization history, the house mouse hybrid zone (HMHZ) is older in the southeast than in the north; however, as argued by Baird and Macholán (2012), its age is old enough to settle into quasi-equilibrium allowing intermixing neutral variants.…”