Interactions between adaptive divergence and gene flow: Implications for the evolutionary ecology of metacommunities.
Hendry, Andrew1, Rasanen, Katja*,1, 1 Redpath Museum and Dept. of Biology, Montreal, Quebec, Canada
ABSTRACT- Any metacommunity theory that seeks to incorporate evolution will have to consider the negative impacts that gene flow between ecological environments can have on adaptive divergence. This point is widely recognized and uncontroversial. Less widely recognized is the opposite causal pathway: adaptive divergence can influence gene flow. Specifically, populations adapted to different environments should exchange fewer genes because of selection against migrants and hybrids (i.e., ecological reproductive isolation). The arrow of causality can thus fly both ways between adaptive divergence and gene flow. We provide theoretical and empirical evidence for the negative impacts of gene flow and adaptive divergence on each other. We then discuss the implications of these interactions for the evolution of biological diversity. For example, the two causal pathways may be coupled in a positive feed-back loop: an increase in adaptive divergence reduces gene flow which allows further adaptive divergence. This feedback should accelerate both adaptive divergence and speciation. It may also have community level effects because the degree of adaptive divergence will influence the strength and asymmetry of interactions between species. No studies have yet considered both causal pathways in the context of metacommunities. We will provide some suggestions as to how such endeavors might proceed.
Key words: adaptive divergence, ecological speciation, gene flow, metacommunity
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