General Biology Seminar

All animals are multicellular, yet little is known about how animal multicellularity first evolved.  The choanoflagellate Salpingoeca rosetta is one of the closest living relatives of animals and its study promises to illuminate the origin of animal multicellularity. Just as animals develop from a single cell – the zygote – a single cell of S. rosetta can produce a multicellular rosette colony through multiple rounds of cell division coupled with stable cell adhesion. S. rosetta and other choanoflagellates express signaling and adhesion genes that are essential for animal multicellularity. One of these genes, a C-type lectin, is required for the development of rosettes and may have regulated multicellularity in the last common ancestor of animals. The switch to rosette development is regulated by specific lipid signals produced by environmental bacteria, raising the possibility that choanoflagellates may illuminate mechanisms underlying host-microbe interactions. In my talk, I will describe our studies of intrinsic and extrinsic factors that regulate the switch to rosette development and discuss the implications of our findings for our understanding of animal origins and development.