The aim of this project is to gain insight into how multicellularity evolved. We investigate this in Dictyostelia social amoebae, a well-defined branch of Amoebozoa, where multicellularity evolved some 600 million years ago. These amoebae grow as single cells but aggregate and develop as multicellular organisms. This enables experimental separation of the uni- and multicellular stages and has made Dictyostelia popular as models for evolution of multicellularity. Historically, evolution has been studied from a protein centered perspective. In the proposed research, we will investigate the contribution of non-coding (nc)RNAs to multicellularity, focusing on a new class of RNAs, Class I RNAs – involved in early multicellular development. For these studies, we use computational analyses to trace the evolutionary appearance of these ncRNAs using the many sequenced species of Dictyostelia. Furthermore, in order to gain understanding of functions of these ncRNAs in evolution, we will take advantage of the well-established Dictyostelia genetic model Dictyostelium discoideum, allowing for detailed molecular analyses of different processes underlying e.g. multicellular development. Hence, with our approach we will address a fundamental question - the involvement of regulatory non-coding RNAs in the transition from uni- to multicellular life styles.