Ancestors of the Animals

The classification of choanoflagellates in the tree of life has long been debated. It was only through the analysis of their genomes that it was revealed they are the closest relatives to multicellular animals (Metazoa). The observation that even today’s living choanoflagellates can form colonies supports the idea that this may have led to the evolution of multicellularity. Interestingly, the same genes responsible for colony formation in choanoflagellates are also involved in maintaining cellular cohesion in multicellular organisms.