One of my interests is the early evolution of animals. How did the first animal look like, and how did it evolve from single-celled species? In particular I am interested in genes that regulate how other genes are used and how these may have contributed to the evolution of increased morphological and developmental complexity. Species I am currently studying are sponges, comb jellies and the single-celled choanozoans, the closest ancestors of animals.

Regulatory RNA


MicroRNAs are short RNA molecules that regulate other genes, and in animals microRNAs are an essential part of the genetic toolkit. I am trying to find out when microRNAs and the complementary protein machinery evolved in animals. We have recently discovered for the first time microRNAs, as well as homolohs of the animal protein machinery which processes the miRNAs, in unicellular ancestors of animals, suggesting that these evolved much earlier than previously thought. The paper has recently been published in Current Biology.

Sphaeroforma arctica, one of our unicellular ancestors. Photo: Jon Bråte.
Figure from the Current Biology paper showing the distribution of the Microprocessor proteins and miRNAs in animals and their single-celled relatives.

Long non-coding RNAs

Another type of regulatory genes are long non-coding RNAs. This is a class of recently discovered RNA genes. Very little is known about what these genes do, and even less is known about their evolutionary significance. To get a glimpse of how the last common ancestor of animals might have used lncRNAs, we have studied their expression dynamics during cellular development in the sponge Sycon ciliatum (published in Proceedings B) and in the ichthyosporean Sphaeroforma arctica (preprint available on bioRxiv).

in situ hybridization of lncRNAs expressed in the oocytes of the sponge Sycon ciliatum. Photo: Jon Bråte.
A heatmap of 70 lncRNAs with correlated expression patterns of coding genes during cellular development of S. arctica. Figure: Dudin et al. 2019. bioRxiv.