PT - JOURNAL ARTICLE AU - Jose Carrasco-Pujante AU - Carlos Bringas AU - Iker Malaina AU - Maria Fedetz AU - Luis Martínez AU - Gorka Pérez-Yarza AU - María Dolores Boyano AU - Mariia Berdieva AU - Andrew Goodkov AU - José I. López AU - Shira Knafo AU - Ildefonso M. De la Fuente TI - Unicellular associative conditioning: an interspecies analysis AID - 10.1101/2020.10.19.346007 DP - 2020 Jan 01 TA - bioRxiv PG - 2020.10.19.346007 4099 - http://biorxiv.org/content/early/2020/10/21/2020.10.19.346007.short 4100 - http://biorxiv.org/content/early/2020/10/21/2020.10.19.346007.full AB - The capacity to learn new systemic behaviour is a fundamental issue to understand the adaptive mechanisms involved in cellular evolution. We have recently observed, in a preliminary analysis, the emergence of conditioned behaviour in individual amoebae cells. In these experiments, cells were able to acquire new migratory conduct and remember it for long periods of their cellular cycle, forgetting it later on. Here, following a similar conceptual framework of Pavlov’s experiments, we have exhaustively studied the migration trajectories of more than 2000 individual cells belonging to three different species: Amoeba proteus, Metamoeba leningradensis, and Amoeba borokensis. Fundamentally, we have analysed several properties of conditioned cells, such as the intensity of the responses, the directionality persistence, the total distance traveled, the directionality ratio, the average speed, and the persistence times. We have observed that these three species can modify the systemic response to a specific stimulus by associative conditioning. Our main analysis shows that such new behaviour is very robust and presents a similar structure of migration patterns in the three species, which was characterized by the presence of conditioning for long periods, remarkable straightness in their trajectories and strong directional persistence. Our quantitative results, compared with other studies on complex cellular responses in bacteria, protozoa, fungus-like organisms and metazoans, allow us to conclude that cellular associative conditioning might be a widespread characteristic of unicellular organisms. This finding could be essential to understand some key evolutionary principles involved in increasing the cellular adaptive fitness to microenvironments.Competing Interest StatementThe authors have declared no competing interest.