A research team from the Cavanilles Institute of Biodiversity and Evolutionary Biology (ICBiBE) and the University of Hull (United Kingdom) has revealed which genes of rotifers (a group of microscopic aquatic invertebrates) allow the adaptation of these to fluctuations in the environment where they live. In the work published in the Scientific Reports journal (from Nature Research), 164 genes potentially responsible for this adaptation were detected, among more than 4,500 studied.
The laboratory of Evolutionary Ecology of the ICBiBE, institute of the Universitat de València (Science Park), had already demonstrated the adaptation of the rotifers to the environmental variations (floods or drought periods of the lagoons) by strategies of minimization of risks (bet hedging). These consist of temporarily advancing the period of sexual reproduction and ensuring that they produce latent resistance eggs, even at the cost of temporarily sacrificing reproductive capacity in unpredictable environments.
“In this study it is detected which genes change together with the production guidelines of resistant latent forms (in this case, resistance eggs) to face the level of environmental unpredictability. This demonstrates the ability of adaptive genetic differentiation between populations that are very close to each other, specifically in the set of La Mancha lagoons where the study has been carried out”, highlights Dr. Lluís Franch-Gras, first author of the article.
For this, in the research – which forms part of the doctoral thesis of Lluís Franch-Gras – the genome of Brachionus plicatilis has been sequenced for the first time, a rotifer widely used in evolution and ecology studies, as well as in aquaculture for the feeding larvae of fish and crustaceans. After that, the genetic divergence between populations has been analysed. “Our work shows the importance of international collaborations; The contribution of Dr. África Gómez and her team (University of Hull, U.K.) has been crucial”, says professor María José Carmona, co-director of the thesis.
It is the first study performed with these invertebrates at the genomic level that considers multiple genotypes of several populations. Only in this way was it possible to determine the genetic basis of adaptation to environmental unpredictability, with the identification of 164 candidate genes to be under selection.
According to professor Manuel Serra, co-director of the thesis, “the development of genomics opens the way to extend the general framework of evolutionary theory, which implies, on the one hand, unequivocally prove that ecology determines, through adaptation to the medium, the features of the organisms, and on the other hand identify which genes are responsible for those traits”.
Besides, María José Carmona adds: “The theory predicts that global change will increase the unpredictability of environmental fluctuations, and it is expected that the organisms that are better adapted to these fluctuations will be the best prepared to face this challenge”. “The recently published work focuses on the analysis of complete genomes and detects for the first time genes associated with adaptation to environmental unpredictability”, adds Professor Eduardo García-Roger, a member of the research team.
This work strengthens the links between ecology and biological evolution. From an applied perspective, invertebrates studied at work are crucial in the maintenance of food chains. Many other living beings that are part of these chains, such as waterfowl, depend on its adaptive success.
The research developed and published in the Scientific Reports article is part of the research project CGL2012-30779, funded by the Ministry of Economy and Competitiveness and co-financed by the European Union with FEDER funds.
Franch-Gras, L., Hahn, C., García-Roger, E. M., Carmona, M. J., Serra, M. & Gómez, A. (2018). Genomic signatures of local adaptation to the degree of environmental predictability in rotifers. Scientific reports, 8(1), 16051. Link: https://www.nature.com/articles/s41598-018-34188-y
(From left to right). Lluís Franch-Gras, María José Carmona, Manuel Serra & Eduardo García-Roger, of the Cavanilles Institute of Biodiversity and Evolutionary Biology.