Multiple pre- and postzygotic components of reproductive isolation between two co-occurring Lysimachia species
- PMID: 36683441
- DOI: 10.1111/nph.18767
Multiple pre- and postzygotic components of reproductive isolation between two co-occurring Lysimachia species
Abstract
Genetic divergence between species depends on reproductive isolation (RI) due to traits that reduce interspecific mating (prezygotic isolation) or are due to reduced hybrid fitness (postzygotic isolation). Previous research found that prezygotic barriers tend to be stronger than postzygotic barriers, but most studies are based on the evaluation of F1 hybrid fitness in early life cycle stages. We combined field and experimental data to determine the strength of 17 prezygotic and postzygotic reproductive barriers between two Lysimachia species that often co-occur and share pollinators. We assessed postzygotic barriers up to F2 hybrids and backcrosses. The two species showed near complete RI due to the cumulative effect of multiple barriers, with an uneven and asymmetric contribution to isolation. In allopatry, prezygotic barriers contributed more to reduce gene flow than postzygotic barriers, but their contributions were more similar in sympatry. The strength of postzygotic RI was up to three times lower for F1 progeny than for F2 or backcrossed progenies, and RI was only complete when late F1 stages and either F2 or backcrosses were accounted for. Our results thus suggest that the relative strength of postzygotic RI may be underestimated when its effects on late stages of the life cycle are disregarded.
Keywords: Lysimachia arvensis; F2 hybrids; backcrosses; flowering phenology; gene flow; pollinator-isolation; speciation.
© 2023 The Authors. New Phytologist © 2023 New Phytologist Foundation.
References
-
- Anderson E, Hubricht L. 1938. Hybridization in Tradescantia. III. The evidence for introgressive hybridization. American Journal of Botany 25: 396-402.
-
- Arista M, Talavera M, Berjano R, Ortiz PL. 2013. Abiotic factors may explain the geographical distribution of flower colour morphs and the maintenance of colour polymorphism in the scarlet pimpernel. Journal of Ecology 101: 1613-1622.
-
- Baack E, Melo MC, Rieseberg LH, Ortiz-Barrientos D. 2015. The origins of reproductive isolation in plants. New Phytologist 207: 968-984.
-
- Brys R, Broeck AV, Mergeay J, Jacquemyn H. 2014. The contribution of mating system variation to reproductive isolation in two closely related Centaurium species (Gentianaceae) with a generalized flower morphology. Evolution 68: 1281-1293.
-
- Cahenzli F, Bonetti C, Erhardt A. 2018. Divergent strategies in pre-and postzygotic reproductive isolation between two closely related Dianthus species. Evolution 72: 1851-1862.
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