The Starlet Sea Anemone Nematostella vectensis: An Anthozoan Model Organism for Studies in Comparative Genomics and Functional Evolutionary Developmental Biology

INTRODUCTION

Nematostella vectensis is a brackish water sea anemone of the family Edwardsiidae. The polyps can be reared with a full life cycle in laboratories with direct access to seawater or in inland laboratories. Robust protocols for the induction of gametogenesis have been established, which can yield thousands of embryos every day and allow for fairly synchronized development of individual batches. Embryos develop into primary polyps within 7-9 d and sexual maturity is reached after 3-6 mo. Zygotes are accessible for most modern molecular and developmental techniques, including gene knockdown by morpholino injection, generation of transgenics, in situ hybridization, and antibody staining. Various cDNA libraries and a bacterial artificial chromosome (BAC) library are available and the genome has been sequenced at ~6.5X coverage. The diploid set of chromosomes is 30 and, based on the sequence assembly, the genome size is 450 Mbp. Expressed sequence tag (EST) and genome analyses have emphasized the striking degree of sequence conservation and complexity in terms of gene content between Nematostella and vertebrates. This indicates that many ancestral traits have been preserved in Nematostella. Taken together with its experimental tractability, this makes Nematostella a very attractive model system among the representatives of basal metazoan lineages.