EMBO Fellows Meeting 2012

Jens Fritzenwanker
EMBO Fellows Meeting 2012
Evolution of the bilaterian trunk; insights from the unsegmented hemichordate
Saccoglossus kowalevskii
Abstract
My current research focuses on the mechanisms underlying the development of the bilaterian trunk and its
evolution. In contrast to non-bilaterian animals, such as cnidarians, bilaterians have an anteroposterior (AP)
axis that is divided into two major regions; the head and the trunk. How mechanisms of trunk development
arose at the base of the bilaterians is not clear, and comparative data are sparse. All bilaterians investigated so
far are animals with segmented body plans, which have posteriorly-localized, terminal growth zones from
which tissue is subsequently added to the elongating AP axis. In these animals posterior growth is always
linked to segmentation, which makes these two mechanisms difficult to study independently. This linkage has
further led to the hypothesis that posterior growth and segmentation evolved together at the base of all
bilaterians, which supports the hypothesis that mechanisms of segmentation are homologous between
protostomes and deuterostomes. However, the inability to untangle mechanisms of segmentation from
posterior growth makes it a challenge to reconstruct the early origins of the trunk. I therefore selected the
unsegmented hemichordate Saccoglossus kowalevskii to determine what components of posterior
growth/segmentation-networks shared between chordates and arthropods are uniquely involved in posterior
growth. I am currently exploring these mechanisms by characterizing the gene regulatory networks regulating
posterior patterning during trunk development and plan to extend my work into analyzing posterior stem cell
behavior.
Jens H. Fritzenwanker, Christopher Lowe
Hopkins Marine Station of Stanford University, 120 Oceanview Boulevard, 93950 Pacific Grove, CA, USA
14-17 June 2012, Heidelberg, Germany