Origin of animal multicellularity

The transition from unicellular eukaryotes to multicellular animals is arguably among the most profound evolutionary transitions in the history of life. The overall aim of this project is to understand which genetic and developmental mechanisms that made this transition possible.


Sphaeroforma arctica, one of our closest ancestors. Photo: Jon Bråte, UiO.


  • Understand the origin of animal multicellularity and development
  • Study the genetic basis behind cellular morphologies in Ichthyosporea

Methods we are using

We compare gene expression data from different developmental stages, both within and between species. Recently we have developed a technique for single-cell transcriptomics of the non-model organism Sphaeroforma arctica. This is an adaptation of the SMART-Seq2 protocol and includes isolation and documentation of single cells and a separate lysis step optimized for the tough cell wall covering these cells. Currently we are implementing the UMI-based protocols for an absolute measure of gene expression, accounting for PCR-bias during library preparation.

Species we are studying

We study species from the most basal animal lineages (comb jellies and sponges) as well as the closest ancestors of animals, Choanozoa (figure 1). This is crucial to studies of animal origin and early evolution was well as for reconstruction of the animal ancestor.

Figure 1. Phylogenetic tree of animals including the unicellular ancestors of animals, Choanozoa.




This project is financed by the Norwegian Research Council (grants nr. 240284 and nr. 213707).


Tools and resources

Available cultures

Sphaeroforma sp.

Pirum gemmata

Abeoforma whisleri


Tags: Evolution, Multicellularity, Animals, Protists, Transcriptomics, single-cell, Developmental biology
Published Apr. 19, 2017 12:24 PM - Last modified Oct. 15, 2019 12:36 PM


Detailed list of participants