A chromosome-scale epigenetic map of the Hydra genome reveals conserved regulators of cell state.

The epithelial and interstitial stem cells of the freshwater polyp Hydra are the best-characterized stem cell systems in any cnidarian, providing valuable insight into cell type evolution and the origin of stemness in animals. However, little is known about the transcriptional regulatory mechanisms that determine how these stem cells are maintained and how they give rise to their diverse differentiated progeny. To address such questions, a thorough understanding of transcriptional regulation in Hydra is needed. To this end, we generated extensive new resources for characterizing transcriptional regulation in Hydra, including new genome assemblies for Hydra oligactis and the AEP strain of Hydra vulgaris, an updated whole-animal single-cell RNA-seq atlas, and genome-wide maps of chromatin interactions, chromatin accessibility, sequence conservation, and histone modifications. These data revealed the existence of large kilobase-scale chromatin interaction domains in the Hydra genome that contain transcriptionally coregulated genes. We also uncovered the transcriptomic profiles of two previously molecularly uncharacterized cell types: isorhiza-type nematocytes and somatic gonad ectoderm. Finally, we identified novel candidate regulators of cell type-specific transcription, several of which have likely been conserved at least since the divergence of Hydra and the jellyfish Clytia hemisphaerica more than 400 million years ago.

AniProtDB: A Collection of Consistently Generated Metazoan Proteomes for Comparative Genomics Studies.

To address the void in the availability of high-quality proteomic data traversing the animal tree, we have implemented a pipeline for generating de novo assemblies based on publicly available data from the NCBI Sequence Read Archive, yielding a comprehensive collection of proteomes from 100 species spanning 21 animal phyla. We have also created the Animal Proteome Database (AniProtDB), a resource providing open access to this collection of high-quality metazoan proteomes, along with information on predicted proteins and protein domains for each taxonomic classification and the ability to perform sequence similarity searches against all proteomes generated using this pipeline. This solution vastly increases the utility of these data by removing the barrier to access for research groups who do not have the expertise or resources to generate these data themselves and enables the use of data from nontraditional research organisms that have the potential to address key questions in biomedicine.

Perceptions of uncertainties about carrier results identified by exome sequencing in a randomized controlled trial.

How individuals perceive uncertainties in sequencing results may affect their clinical utility. The purpose of this study was to explore perceptions of uncertainties in carrier results and how they relate to psychological well-being and health behavior. Post-reproductive adults (N = 462) were randomized to receive carrier results from sequencing through either a web platform or a genetic counselor. On average, participants received two results. Group differences in affective, evaluative, and clinical uncertainties were assessed from baseline to 1 and 6 months; associations with test-specific distress and communication of results were assessed at 6 months. Reductions in affective uncertainty (∆x̅ = 0.78, 95% CI: 0.53, 1.02) and evaluative uncertainty (∆x̅ = 0.69, 95% CI: 0.51, 0.87) followed receipt of results regardless of randomization arm at 1 month. Participants in the web platform arm reported greater clinical uncertainty than those in the genetic counselor arm at 1 and 6 months; this was corroborated by the 1,230 questions asked of the genetic counselor and residual questions reported by those randomized to the web platform. Evaluative uncertainty was associated with a lower likelihood of communicating results to health care providers. Clinical uncertainty was associated with a lower likelihood of communicating results to children. Learning one's carrier results may reduce perceptions of uncertainties, though web-based return may lead to less reduction in clinical uncertainty in the short term. These findings warrant reinforcement of clinical implications to minimize residual questions and promote appropriate health behavior (communicating results to at-risk relatives in the case of carrier results), especially when testing alternative delivery models.