Evolutionary biologists at Skoltech discovered the existence of recombination and exchange of genetic material in bdelloid rotifers, microscopic freshwater creatures. For a long time it was believed that bdelloid rotifers completely abandoned sexual reproduction several tens of millions of years ago. This called into question the hypothesis that sexual reproduction is necessary for the long-term evolutionary success of a group of species. But according to a study published in the journal Nature Communications, rotifers do exchange genes.
Sexual reproduction, characterized by recombination and the exchange of genetic information between different individuals of the same species, is an evolutionarily necessary process that helps species to adapt to changing environmental conditions and survive. Transitions to asexual reproduction in eukaryotes occur quite often, but usually lead to rapid extinction. On this basis, the transition to asexual reproduction is usually viewed as an “evolutionary dead end”. However, there are likely exceptions to this rule - a group of ancient asexual organisms. For a long time, bdelloid rotifers, microscopic invertebrates, which presumably switched to asexual reproduction several tens of millions of years ago, were considered one of the most striking examples of such a group.
An international group of scientists led by Georgy Bazykin, Professor of the Skoltech Life Sciences Center and Alexei Kondrashov, Professor at Moscow State University, using the example of the bdelloid rotifer Adineta vaga, showed that the processes of recombination and exchange of genetic material in rotifers of this group are still present.
Scientists analyzed 11 complete rotifer genomes and found “traces” of recombination and exchange of genetic material between A. vaga individuals.
“We have shown that the structure of the intraspecific variation in A. vaga is incompatible with exclusively asexual reproduction and the absence of recombination. Bdelloid rotifers have long been considered an “evolutionary scandal”. However, our results indicate that, in all likelihood, the status of bdelloid rotifers as an ancient asexual group should be revised. Our results are fundamental to evolutionary biology as they highlight the need for recombination for the long-term evolutionary success of species. It should be noted that, despite the fact that some of our data support the existence of meiosis in bdelloid rotifers, the mechanisms of genetic material exchange and recombination in bdelloid rotifers remain unclear and are of great interest for future research", - comments the first author of the study, junior scientific Skoltech employee Olga Vakhrusheva.
Skoltech is a non-governmental international university. Created in 2011 in partnership with the Massachusetts Institute of Technology (MIT), Skoltech trains a new generation of leaders in science, technology and business, conducts research in disruptive fields and fosters technological innovation to address the most pressing challenges facing Russia and the world. Skoltech develops six priority areas: data science and artificial intelligence, life and health sciences, modern design methods and advanced materials, energy efficiency, photonics and quantum technologies, and advanced research.