The genetics of species adaptation
Invasive species impose an economic burden all over the world, including the countries of the European Union. It is very important that research investigates all aspects of invasion, including genetics and invasion dynamics. The bank vole is a small rodent, found through much of Eurasia and was first detected in Ireland in the 1960s. This small mammal shows a rapid spreading pattern, representing an excellent natural experiment in invasion genetics. The EU-funded 'Genetics of an invasive species and its parasites: the bank vole in Ireland' (INVASIVOLE) project worked on reconstructing the invasion history of the bank vole and its genetic diversity during expansion. Using data from a field campaign and previous surveys on bank vole distribution, researchers estimated the rate of expansion to be approximately 2.5 kilometres per year. Genotypic analysis of 281 animals from different sites for nearly 6 000 single nucleotide polymorphism loci provided invaluable information about the genetic diversity of these animals. The sampling sites that were used represented different points along the axis of expansion, ranging from the site of introduction to the wave front of the ongoing expansion. Researchers detected a decline in genetic diversity as the population expanded its range. They identified mutations capable of driving selection. Candidate genes included some that could influence behaviour or immunological function. To assess the fitness of the expanding population and associate it with the reduced genetic diversity, scientists performed morphometric analysis of the animals. Combining these data with analyses of parasites of the same animals would help portray a better picture of the history of invasion of the bank vole. Overall, INVASIVOLE outcomes provide an example of how invasion genetics can help understand the complex process of invasion. Implementation of the generated information for pest control could prove beneficial for biodiversity, ecosystem integrity, agriculture, fisheries and public health.
Keywords
Species, adaptation, invasion, genetics, bank vole, single nucleotide polymorphism, morphometry, parasite analyses
