Accepted_test

The investigation of colonial invertebrates provides a new perspective on a number of important biological processes such as maintenance of adult stem cells, transdifferenciation, and cyclic degeneration of organs and tissues. The molecular basis of coloniality is poorly understood, with only a few model species from hydroids and ascidians providing insights. Bryozoans, in particular, remain an understudied group in this regard. Our study on Cristatella mucedo is the first step in addressing this gap for Bryozoa. We sequenced the transcriptomes of 6 consecutive stages of colony polypides of C. mucedo development (from polypide bud to degenerating polypide) on the Illumina HiSeq2500 platform, constructed a hight-quality reference de novo transcriptome and performed differential gene expression analysis, identified gene co-expression clusters and characterized them using GO and KO group enrichment analyses. Our focus was on genes related to stemness, developmental processes, cell death, and their regulation. We have identified the most promising genes, processes and suggest the most probable signaling pathways (mTOR and Wnt/beta-catenin signaling pathways) that regulate both bud development and polypide lifespan. In addition, our findings indicate that polypide degeneration is a similarly complex and regulated process as budding, representing a promising area for further research.