[Seminar] The mouth, the anus and the blastopore. Their questionable developmental and evolutionary relationships and the origin of the animal gut by Prof. Andreas Hejnol

Abstract:

The alimentary canal with two openings is a key invention in animals because
it allows to digest food in a more efficient way often leading to an increa
se the body size. The evolutionary origin of the animal digestive tract play
ed also a key-role in many scenarios about the evolution of bilaterian anima
ls. These have been heavily Influenced by Haeckel's "biogenetic law" in that
the gut development in a few bilaterian species has been interpreted as rec
apitulation of ancient evolutionary transitions. But recent molecular phylog
enies and novel developmental data challenge these old scenarios and raise n
ew questions about its origin. Is there indeed a tight evolutionary and deve
lopmental relationship between the digestive openings and the embryonic blas
topore as suggested in terms such as protostomy and deuterostomy? How often 
and when did the orifices to the digestive tract arose and from what did the
y come from? Answering these questions will ultimately draw a different pict
ure about the evolution of the digestive tract. Especially the finding that 
the mouth and anus formation are independent from the gastrulation process s
heds new light on the evolution of the digestive system and provides the opp
ortunity to develop new, testable hypotheses about the origins of the digest
ive orifices. We will present new embryological data of different animal lin
eages that shed light on the evolutionary origin of the animal digestive tra
ct and body openings.

Bio:

Andreas Hejnol is research group leader at the Sars International Centre for Marine Molecular Biology in Bergen, Norway. After obtaining his Ph.D. in Comparative Zoology from the Free University Berlin, Germany in 2002 he worked as a postdoctoral fellow in the laboratory of Ralf Schnabel in Braunschweig and at the Kewalo Marine Laboratory in the lab of Mark Q. Martindale in Hawaii. He started his research group “Comparative Developmental Biology” at the Sars Centre in 2009. His current research interest on descriptive, experimental molecular developmental biology of a broad range of invertebrates and includes comparative genomic approaches and phylogenomics. The main research goal is to understand the evolutionary origin and diversification of animal body plans. He is ERC Consolidator Grant holder and received for his achievments in evolutionary developmental biology and comparative zoology the Alexander O. Kovalevsky Medal from the St. Petersburg Society for Naturalists in 2018.