Evolutionary genetics of invasive species Carol

Carol Eunmi Lee Dept of Zoology, 430 Lincoln Drive, University of Wisconsin, Madison, WI 53706, USA. e-mail: carollee@ facstaff.wisc.edu INVASIVE SPECIES (see Glossary) and populations pose major threats to biodiversity, ecosystem integrity, agriculture, fisheries, and public health. Economic costs associated with the more publicized exotic invaders, such as weeds, agricultural pests, zebra mussels and plant pathogens, total ~US$137 billion y−1 in the USA [1]. The rapid spread of exotics has received considerable attention within the international community, and has mobilized substantial ecological research. By contrast, evolutionary aspects of INVASIONS have remained relatively unexplored. Why is evolution integral to the study of invasion biology? Invasions frequently constitute rapid evolutionary events [2], resulting in populations that are genetically dynamic over both space and time. Genetic characteristics of populations have profound impacts on their capacity for range expansions [3–5]. Both natural selection and genetic drift could alter genetic structures of invading populations in ways that modify their tolerance or behavior (see examples below). Invading populations are also capable of inducing evolutionary changes in native species [6,7]. Consequently, incorporating evolutionary genetics is important for revealing characteristics that determine invasion success. Why is this topic of immediate importance? As impacts of invasions intensify, it is imperative to move beyond treating invasive species as genetic black boxes in mitigation and management strategies. For instance, demographic models that treat invasive species as homogeneous and immutable entities will often fail over extensive spatial or temporal scales. We are in an excellent position to investigate factors that affect invasion success, given recent developments in evolutionary theory and molecular genetics. Technical innovations in GENOMICS (e.g. MICROARRAY TECHNOLOGY and QUANTITATIVE TRAIT LOCI (QTL) MAPPING) and BIOINFORMATICS offer many opportunities for exploring GENETIC ARCHITECTURE and gene expression patterns of invading populations. Effective application of these tools requires an assessment of the current literature. Thus, here I review recent studies on genetic characteristics and adaptative responses of successful invaders, and recommend topics for future research.