Project Summary The camera on our main research microscope has failed and we are functioning only through a loaner from our microscope representative. We request support through this administrative supplement mechanism to replace the 5-series camera and upgrade the system from Windows 7, ZenLite imaging software. This microscope and camera are our workhorses in the lab for imaging microinjections and micromanipulations, live embryo imaging, whole mount immune localization and RNA-hybridization imaging. We can function only as long as the representatives from Zeiss allow us to keep the loaner camera. The research supported by this request is focused on understanding the mechanisms of formation of primordial germ cells during embryogenesis, how they form during early development, and how they regenerate when the originals are removed. Our work leverages embryos from a sister group to chordates – the sea star and sea urchin. While not common organisms for biomedical research, these echinoderms have many strategic benefits for revealing unique perspectives in the biology of germline formation and regeneration. Millions of synchronous embryos from a single male/female cross allow biochemical and metabolic analysis of the germline, the resultant embryos have ideal transparency for in vivo longitudinal imaging, they develop rapidly, are easy to manipulate (single cell drop-mRNA-seq, optogenetics, cell and tissue transplantations) and they are well suited to complementary gene perturbation approaches (CRISPR/Cas9, morpholino antisense oligonucleotides, MASO), and small molecule perturbations. The existing deep genomic and reagent resources for these animals, coupled with their tractable experimental characteristics, yields a unique system for understanding primordial germ cell biology with defined molecular and morphological endpoints, in live embryos with longitudinal analysis, distinct metrics of quantitation, and transgenerational evaluations.