How fast does the speciation clock tick in selfing versus outcrossing lineages?

Informations

Funding country

Norway

Acronym

-

URL

-

Start date

1/1/2018

End date

12/31/2023

Budget

2,142,783 EUR

Fundings

Abstract

Species are the most fundamental unit in nature, yet we know surprisingly little about how long it takes for new species to arise and what factors influence the rate of speciation (the ticking of the speciation clock). Recently, we found that new species may develop at astonishing speed in Arctic self-pollinating plants. This is important because many wild and cultivated plants are more or less self-fertilizing. In this project, we develop and test theoretical models of how self- and cross-fertilization can affect genetic architecture and rate of speciation. We work with a large set of different species. For each species, we cross different populations and examine the resulting hybrids for fertility. If the hybrids are fully or partly sterile, the parental populations are on their way to evolve into new species. We use genomic analyses to estimate parental divergence time and rate of self-fertilization. We also raise second-generation hybrids to enable more detailed genomic analyses. We use the African sky archipelago as the main study system, because the populations on these isolated high mountains represent a wide range of divergence times. We arranged extensive field expeditions to six of the highest African mountains, and the collected plants were cultivated at UiO. All crossing experiments and fertility analyses are finalized, and the genomic data are collected and partly analyzed (except for the second-generation hybrids, currently under sequencing). Delays caused by the corona epidemic made it necessary to merge the current datasets with some unpublished datasets from our previous RCN project. Preliminary analyses of this merged dataset suggest that self-fertilization speeds up the speciation process, in agreement with our predictions developed in the theoretical part of the project. The project has already resulted in a number of scientific and popular contributions, including several spin-off scientific papers on sky island evolution, speciation, and development of genomic resources (e.g. in PNAS, Molecular Ecology). One of the core theoretical papers is accepted in PLOS Genetics. We are confident that the project makes a significant contribution to our understanding of the speciation process, and it may also help to improve crop breeding. Many crops are self-pollinating and may quickly develop crossing barriers towards their wild relatives, from which we need to collect new genes to improve resistance against diseases and environmental change.