Genetic architecture and evolutionary change in the invasive Northern Pacific sea star

Invasive species provide valuable study systems to evaluate evolutionary and ecological processes occurring during the colonization of new habitats. Exposure to novel environmental conditions experienced upon introduction can... [ view full abstract ]

Invasive species provide valuable study systems to evaluate evolutionary and ecological processes occurring during the colonization of new habitats. Exposure to novel environmental conditions experienced upon introduction can generate strong selective pressures, eliciting rapid evolutionary change in morphological, physiological and life history traits. While considerable research has documented the ecological aspect of biological invasions, we still know relatively little about the underlying genetic basis of these often observed adaptive changes and how physiological responses and associated underlying genetic mechanisms facilitate environmental adaptation and invasion success. Using a combination of microsatellite and transcriptomic genetic data, we explore patterns of divergence between native and invasive Asterias amurensis populations. Our results suggest that the source of the Australian introduction is likely to have occurred from Tokyo Bay, Japan, which resulted in the loss of neutral genetic diversity within the invasive range. However, our comparative RNA-Seq experiment shows substantial gene expression divergence between native and invasive populations for a number of important genes with putative roles in immune function and the response to environmental stress. These patterns of divergence may reflect selection for alleles in invasive populations that perform better in novel environmental conditions and may indicate rapid local adaptation during the invasion into Australia.