Project outline Diapause is a natural process by which an organism enters a state of suspended animation in response to environmental challenges. Diapause is unique from other dormancies (e.g. quiescence) as the stage, entry and length of developmental arrest is endogenously programmed in advance of onset, and may be either facultative or obligatory. The biomedical model organism Daphnia produces diapausing embryos as part of its reproductive cycle. When buried in the lake sediments, these embryos produce a living archive of past populations that can be sampled and resuscitated in the laboratory after prolonged periods of time. Investigators at the University of Birmingham have hatched these dormant embryos to resume development, producing healthy reproductive adults, even after 700 years of sustained developmental arrest. From these hatchlings, populations of Daphnia that are native to Europe and to North America are indefinitely maintained in the laboratory for evolutionary studies through 10,000 generations. The work of an MIBTP student (Ms Rosemary Barnett who is now submitting her thesis) discovered that the development of embryos destined to diapause is delayed compared to non-diapausing embryos until arrested, after roughly eleven rounds of cellular divisions (over 3500 cells) whereupon mitotic activity is absent, cytoskeletal components are depleted and cells are condensed for these exceptionally long periods of metabolic inertness. Her analysis by statistical machine learning of a multiomics datasets (transcriptomics and metabolomics), comparing the developmental programmes of both types of embryos, revealed both recognizable and newly discovered regulatory pathways, having significant implications on our understanding of aging. This work is providing links between gene expression and epigenetics, nuclear organization, metabolic output and genome stability that will constitute a new foundation for the study of cell fitness and longevity. This next MIBTP2 PhD Project Proposal follows upon these initial molecular biological findings from observing the entry into diapause, to now discover the process by which a diapausing embryo “senses” environmental cues to subsequently resume development. The student will investigate the degree to which diapausing embryos are reactive to environmental signals and perturbations as a function of time at dormancy, and how being in diapause halts the aging process. Finally, the student will examine whether the breaking of diapause consists of a reversal of molecular and cellular events that had earlier prepared the embryos for suspended animation. Our earlier technological multiomics approach of simultaneously measuring transcriptomics and metabolomics will now be supplemented with epigenomic measurements of chromatin dynamics and transcription, gene silencing/activation, cell cycle progression, apoptosis and differentiation. Dr Iain Macaulay (group leader in technical development) is pioneering new approaches for integrated multiomics of single cells and low-input genome samples at the Earlham Institute. He expressed interest in collaborating on this project since 2017 as a co-leader of the BBSRC supported “National Capability in Genomics and Single Cell Analysis”. UOB collaborations at advising this student will include Professor Mark Viant (metabolomics), Dr Scott Hayward (diapause biology), Professor Jonathan Frampton (stem cell biology) and Professor Ben Brown (statistical machine/deep learning data analysis).