Research Valentina Burskaia

Research team

• Evolutionary ecology group (EVECO)

Expertise

Stunning beauty of living creatures raises an inevitable question: how is it made? According to the second law of thermodynamics, in a closed system entropy always increases irreversibly. However, in the world of constantly increasing entropy evolution builds complexity out of chaos. What are the natural laws under this process? Fortunately, all the 3.7 billion years of life development are carefully documented in every organism’s genome. Every day I learn how to read. Among many fundamental and still not answered questions of evolution my favorite is: what drives sympatric speciation? Indeed, how it happens that some species diverge into hundreds of new species in ridiculously short period of time (like well-known Lake Malawi cichlids), while other species persist as one interbreeding population for millions of years (like hypervariable fungus Schizofillum communae, which is considered as one species despite 20% intraspecific diversity). Here is not an insane question to ask: why the Earth is inhabited by millions of species instead of one hypervariable fungus, like Schizofillum communae? For some species groups none of existing hypothesis give a sufficient answer. I got my master’s degree in Zoology (Lomonosov Moscow State University, Moscow, 2009) and PhD in Bioinformatics (Skoltech, Moscow, 2020) in a hope that acquired skills may help to find hidden patterns of evolution. In PhD project, titled "Positive selection in parallel evolution" I studied the repeatability of adaptive evolution at different phylogenetic distances. Positive selection is something every evolutionary biologist loves: if is a force, which creates new adaptations. However, it's widely accepted, that genome-wide parallel amino acid evolution is mainly governed by genomic constraints and epistatic interactions, not by positive selection. Analyzing a large set of Vertebrata and Invertebrata genomic dataset, I found a striking excess of genome-wide amino acid parallel evolution (let’s call it EGWAAPE) in one of the groups - Lake Baikal Amphipoda. It is a unique case, which only can be explained by positive selection, acting in many regions genome wide. But what kind of adaptation could cause this pattern, and why it is present in almost any of 350 Lake Baikal Amphipoda species? To find an answer, I joined Svardal Lab at the University of Antwerp. Apparently, Lake Baikal Amphipoda species flock belongs to a group of largest species flocks in the world, which is most similar to legendary Lake Malawi Cichlid species flock. My hypothesis is that recently discovered EGWAAPE is a consequence of ancient hybridization, which preceded the burst of 350 Lake Baikal Amphipoda species diversification. Even more that that: we found evidence that this event of ancient hybridization may have facilitated explosive speciation of the group by providing much needed genetic variation. Different parts of ancestral species genomes were combined in new species and used for construction of new adaptations. That may be exactly the reason, why Lake Baikal is inhabited by 350 ecologically specialized forms of gammarids, while other Great Ancient Lakes have almost none. To test this hypothesis, since September 2022 I work on project, called "Does hybridization facilitate explosive speciation of Lake Baikal amphipods?", which is funded by individual MSCA postdoctoral fellowship. Baikal amphipods are a textbook example of rapid speciation, and we expect the study to have an impact on fundamental understanding of explosive speciation events around the world.