RT Journal
A1 Schnitzler, Christine E.
A1 Chang, E. Sally
A1 Waletich, Justin
A1 Quiroga-Artigas, Gonzalo
A1 Wong, Wai Yee
A1 Nguyen, Anh-Dao
A1 Barreira, Sofia N.
A1 Doonan, Liam B.
A1 Gonzalez, Paul
A1 Koren, Sergey
A1 Gahan, James M.
A1 Sanders, Steven M.
A1 Bradshaw, Brian
A1 DuBuc, Timothy Q.
A1 Febrimarsa, 
A1 de Jong, Danielle
A1 Nawrocki, Eric P.
A1 Larson, Alexandra
A1 Klasfeld, Samantha
A1 Gornik, Sebastian G.
A1 Moreland, R. Travis
A1 Wolfsberg, Tyra G.
A1 Phillippy, Adam M.
A1 Mullikin, James C.
A1 Simakov, Oleg
A1 Cartwright, Paulyn
A1 Nicotra, Matthew
A1 Frank, Uri
A1 Baxevanis, Andreas D.
T1 The genome of the colonial hydroid Hydractinia reveals that their stem cells use a toolkit of evolutionarily shared genes with all animals
JF Genome Research 
JO Genome Research 
YR 2024 
FD March 01 
VO 34 
IS 3 
SP 498 
OP 513 
DO 10.1101/gr.278382.123 
UL http://genome.cshlp.org/content/34/3/498.abstract 
AB Hydractinia is a colonial marine hydroid that shows remarkable biological properties, including the capacity to regenerate its entire body throughout its lifetime, a process made possible by its adult migratory stem cells, known as i-cells. Here, we provide an in-depth characterization of the genomic structure and gene content of two Hydractinia species, Hydractinia symbiolongicarpus and Hydractinia echinata, placing them in a comparative evolutionary framework with other cnidarian genomes. We also generated and annotated a single-cell transcriptomic atlas for adult male H. symbiolongicarpus and identified cell-type markers for all major cell types, including key i-cell markers. Orthology analyses based on the markers revealed that Hydractinia’s i-cells are highly enriched in genes that are widely shared amongst animals, a striking finding given that Hydractinia has a higher proportion of phylum-specific genes than any of the other 41 animals in our orthology analysis. These results indicate that Hydractinia’s stem cells and early progenitor cells may use a toolkit shared with all animals, making it a promising model organism for future exploration of stem cell biology and regenerative medicine. The genomic and transcriptomic resources for Hydractinia presented here will enable further studies of their regenerative capacity, colonial morphology, and ability to distinguish self from nonself.