Practice question

Choanoflagellates unicellular and colonial flagellated protists occupy sister lineage to Metazoa within opisthokont supergroup, diverging most recently compared to green algae belonging to Archaeplastida, amoebae within Amoebozoa or ciliates within SAR. Ultrastructural and genomic evidence includes homologous collar of microvilli surrounding flagellum, receptor tyrosine kinases, cadherin repeats, Myc oncogenes and mitochondrial gene synteny. Genera Monosiga, Salpingoeca and colonial Proterospongia demonstrate rosette formation resembling sponge morula. Therefore phylogeny positions choanoflagellates as closest living relatives of animals providing model for multicellularity origin.