Does hybridization facilitate explosive speciation of Lake Baikal amphipods?

The adaptive radiation of amphipods in Lake Baikal has brought forward more than 340 species (20% of the world’s freshwater amphipods), making it one of the largest species flocks after the famous African cichlid radiations, and one of the only large radiations in temperate climates. Despite this iconic status the radiation has not yet been subject to detailed genomic investigation.

During my PhD I was able to demonstrate excessive amounts of parallel adaptation among the transcriptomes of species of this adaptive radiation.

In this project, I will use genomic approaches to test whether the previous results could be explained by hybridisation and adaptive introgression.

These processes have been shown to occur in other adaptive radiations, but their functional role in rapid diversification is still debated.

My preliminary results indicate that hybridization between two independent lineages of Baikalian amphipods emerged in the period when fast speciation started.

Furthermore, I found intriguing signals of positive selection on introgressed loci.Additional data and specific methodology developed in this project will enable me to disentangle the processes governing speciation in this group.

Profiting from strong relevant experience of the host laboratory I will re-analyze available transcriptomic datasets together with newly sequenced genomes.

I will map precise directions of hybridization at the phylogenetic tree, describe functional associations of introgressed loci, test selection signatures associated with introgression, and estimate the extent to which repeatable ecomorphological traits are underpinned by ""reusable"" elements of ancestral genomes.

This research has groundbreaking potential in providing a direct test of a potential catalysing role of hybridization in fast speciation in this system.