| 1. |
- Favre, Adrien, et al.
(författare)
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Differential adaptation drives ecological speciation in campions (Silene) : evidence from a multi-site transplant experiment
- 2017
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Ingår i: New Phytologist. - : WILEY-BLACKWELL. - 0028-646X .- 1469-8137. ; 213:3, s. 1487-1499
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Tidskriftsartikel (refereegranskat)abstract
- In order to investigate the role of differential adaptation for the evolution of reproductive barriers, we conducted a multi-site transplant experiment with the dioecious sister species Silenedioica and S.latifolia and their hybrids. Crosses within species as well as reciprocal first-generation (F-1) and second-generation (F-2) interspecific hybrids were transplanted into six sites, three within each species' habitat. Survival and flowering were recorded over 4yr. At all transplant sites, the local species outperformed the foreign species, reciprocal F-1 hybrids performed intermediately and F-2 hybrids underperformed in comparison to F-1 hybrids (hybrid breakdown). Females generally had slightly higher cumulative fitness than males in both within- and between-species crosses and we thus found little evidence for Haldane's rule acting on field performance. The strength of selection against F-1 and F-2 hybrids as well as hybrid breakdown increased with increasing strength of habitat adaptation (i.e. the relative fitness difference between the local and the foreign species) across sites. Our results suggest that differential habitat adaptation led to ecologically dependent post-zygotic reproductive barriers and drives divergence and speciation in this Silene system.
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| 2. |
- Karrenberg, Sophie, et al.
(författare)
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Ecological divergence plays an important role in strong but complex reproductive isolation in campions (Silene)
- 2019
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Ingår i: Evolution. - : Wiley-Blackwell. - 0014-3820 .- 1558-5646. ; 73:2, s. 245-261
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Tidskriftsartikel (refereegranskat)abstract
- New species arise through the evolution of reproductive barriers between formerly interbreeding lineages. Yet, comprehensive assessments of potential reproductive barriers, which are needed to make inferences on processes driving speciation, are only available for a limited number of systems. In this study, we estimated individual and cumulative strengths of seven prezygotic and six postzygotic reproductive barriers between the recently diverged taxa Silene dioica (L.) Clairv. and S. latifolia Poiret using both published and new data. A combination of multiple partial reproductive barriers resulted in near-complete reproductive isolation between S. dioica and S. latifolia, consistent with earlier estimates of gene flow between the taxa. Extrinsic barriers associated with adaptive ecological divergence were most important, while intrinsic postzygotic barriers had moderate individual strength but contributed only little to total reproductive isolation. These findings are in line with ecological divergence as driver of speciation. We further found extensive variation in extrinsic reproductive isolation, ranging from sites with very strong selection against migrants and hybrids to intermediate sites where substantial hybridization is possible. This situation may allow for, or even promote, heterogeneous genetic divergence.
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