Stanford University

Regulating two distinct body plans from a single genome

Marine invertebrates are characterized by a rich array of life history strategies; some species are direct-developers, like most developmental model species, where the adult body plan emerges straight from the embryo. However, most marine invertebrates have a distinct larval body plan that only develops features of the adult body plan late in larval development, often months following embryogenesis.

Enteropneust hemichordate worms have both direct and indirect-developing species and we work on both types of development in the lab. Schizocardium californicum is a local CA species that has distinct larval and adult body plans. The larvae develop for several months in the plankton before metamorphosing into an adult in a rapid and radical transition that last 24- 48hrs. We are investigating the transition of metamorphosis between the larval and adult body plan at the cellular level to investigate how such rapid reorganization occurs. 

We are taking a genomic approach to investigate how this dramatic transformation takes place and how cellular composition changes through metamorphosis. A collaboration with Pacific BioSciences and Dan Rohksar's lab at UC Berkeley has delivered a very high quality genome assembly. This high quality resource allows the use of a single cell RNAseq approach to determine how the cellular composition of the larval body plan changes through the process of metamorphosis and get back to the question of how a single genome regulates the formation of two distinct body plans. This work is a collaborative effort with BioHub and Dan Rohksar's lab

Relevant Publications:

The development and metamorphosis of the indirect developing acorn worm Schizocardium californicum (Enteropneusta: Spengelidae). In press. Frontiers of Zoology. 

The adult body plan of indirect developing hemichordates develops by adding a hox-patterned trunk to an anterior larval territory. Current Biology (Jan 2017). PMID: 27939313