Animals and Their Unicellular Ancestors

Animals belong to the Opisthokonta, one of the major divisions of the eukaryotic Tree of Life. This supergroup also includes other well?known groups such as fungi and choanoflagellates, in addition to some newly discovered unicellular taxa as the Ichthyosporea or the Filasterea. To unveil the origin of animal multicellularity, it is vital to understand the evolution of their single?celled relatives, as they might hold key genetic clues that might help us understand how the unicellular ancestors of animals became animals. Our current knowledge of unicellular animal relatives, their specific phylogenetic relationships and the role they might play in future research is being improved, thanks to molecular data