Dictyostelium discodieum

The evolutionary transition from unicellular to multicellular organisms remains a fundamental mystery of biology. The explosion of epigenetic complexity at this transitional time point led us to hypothesize that epigenetic changes helped drive the evolution of multicellularity. We are examining this hypothesis in Dictyostelium discodieum, one of the rare organisms which is both unicellular and multicellular.

We recently performed a comprehensive profiling of chromatin state and single cell gene expression in Dictyostelium at both its unicellular and multicellular stages. Unlike the unidirectional development from a unicellular zygote into a multicellular organism, Dictyostelium readily transits back and forth between both differentiated multicellular and unicellular states. By comparing the epigenome of Dictyostelium at both unicellular and multicellular stages to syntenic regions in the unicellular eukaryote S. pombe and the multicellular eukaryote C. elegans, we identify a conserved multicellular chromatin accessibility signature. This work helped to identify specific, conserved epigenetic modifications that facilitate the evolution of multicellularity and demonstrated a critical role for epigenetics in multicellularity. Dictyostelium affords us the capacity to manipulate the genome and epigenome of this organism to identify genes as well as epigenetic modifications that are necessary and sufficient for multicellularity in Dictyostelium.

We are currently using Dictyostelium to examine the role of epigenetics in the evolution of cellular altruism and epigenetic memory.

View here a recent talk Greer gave on METL-5 and Dictyostelium.

Publications