Convergent evolution and loss of a classic floral polymorphism – genetic causes and genomic consequences

Convergent evolution has long fascinated evolutionary biologists, because it can provide insights into adaptation.

An iconic example of convergent evolution is distyly, a floral and reproductive polymorphism that confers outcrossing in flowering plants.

While distyly has evolved at least 13 times, loss of distyly has occurred even more frequently, in association with the evolution of a floral selfing syndrome termed homostyly.

The evolution and loss of distyly thus offers an opportunity to study the role of parallel molecular changes for convergent phenotypic evolution.

Here, we aim to study the genetic basis of evolution and loss of distyly in wild Linum species, a system that is exceptionally well suited for this purpose due to its experimental tractability, genomic tools, and the presence of at least six independent losses of distyly.

Building on our recent identification of the Linum distyly S-locus supergene, we will first dissect the function of the supergene to test whether parallel molecular changes underlie convergent evolution of distyly in the widely diverged Linum and Primula.

We will then investigate whether repeated loss of distyly in Linum is associated with parallel molecular changes and altered selective pressures on floral and reproductive genes.

The results are key for an improved understanding of the genetic basis and genomic consequences of convergent evolution in flowering plants.