The evolution of barriers to gene exchange
Short description
The origin of new species by the splitting of existing species is a key evolutionary process. This process requires the evolution of traits that restrict successful reproduction between divergent populations.
We are studying traits of this type, and their genetic basis, in a coastal marine snail Littorina saxatilis. This snail shows strong adaptation to different habitats, repeatedly throughout its North Atlantic range.
Successful interbreeding between populations in different habitats -ecotypes- is reduced by this differential adaptation, by a tendency of snails to mate with similar individuals and, in some places, by a tendency of snails to choose the appropriate habitat. Genetically, many of the important traits seem to be controlled by chromosomal inversions – structural changes in the genome that hold together many different genes.
