Contingency and determinism during convergent contemporary evolution in the polymorphic land snail, Cepaea nemoralis

摘要: Questions: How replicable is short-term evolution? Do populations recently exposed to analogous habitat gradients show adaptations? Conversely, how important are chance historic events and genetic constraints in shaping the unique aspects of contemporary Organisms: Three Cepaea nemoralis population pairs, each pair inhabiting adjacent open shaded habitats sub-optimal climatic conditions south-eastern Poland. Population pairs likely arose through separate, single introductions were isolated from other populations. Methods: We compared frequencies genetically determined shell variants 18–28 years after establishment Conclusions: The manner by which adaptive divergence proceeded varied geographic location, but effect terms darkness shells was convergent, resulting higher dark-shelled snails light-shelled habitats. Estimated selection coefficients large (0.236, 0.370, 0.420) with respect studies for this species. relatively simple inheritance system colour species ensures that observed differences heritable allows insights into historical roles architecture restricted variation driving shared elements divergence.