We are excited to share a new study led jointly by Dr. Mackenzie Gavery (NOAA Northwest Fisheries Science Center) and Dr. Lauren Vandepas (UW School of Aquatic and Fishery Sciences), who served as co–first authors on a major advance in marine developmental biology and applied aquaculture biotechnology.
The paper — “Primordial germ cell specification and early developmental cell states in Pacific oyster” — provides the earliest single-cell RNA-seq atlas ever produced from a bivalve embryo, capturing the transition from cleavage to gastrulation and revealing when and how primordial germ cells (PGCs) are formed in the Pacific oyster.
📄 Read the open-access paper here
Citation: Gavery, M.R.†, Vandepas, L.E.†, et al. (2025). BMC Genomics 26:951.
Why Germ Cells Matter for Aquaculture
Germ cells give rise to gametes (eggs and sperm) and are the cellular “gatekeepers” of reproduction. For marine aquaculture, the ability to reliably produce sterile animals is essential for:
- Preventing genetic introgression of hatchery lines into wild populations
- Minimizing ecological risk of non-native stock
- Improving meat quality and energy allocation in culture
- Increasing thermal and stress resilience during grow-out
Triploidy has been the only scalable sterility tool used in oysters to date, but its performance declines under environmental stress. This work opens the door to next-generation sterility strategies based on targeted disruption of germ cell formation — an approach already used successfully in some finfish species.
What the Team Discovered
Using droplet-based single-cell transcriptomics, the team tracked more than 29,000 embryonic cells across the earliest developmental stages. Dr. Gavery and Dr. Vandepas identified:
| Developmental Stage | Key Finding |
|---|---|
| Cleavage + Blastula | Germline markers like vasa present but broadly distributed |
| Gastrula | PGCs segregate into a single transcriptionally distinct cluster |
| Marker Signature | Novel oyster-specific PGC genes identified, including spPHI and LOC105328839 |
Importantly, the study not only confirmed known germline markers (vasa, nanos) but uncovered new PGC-associated genes unique to bivalves — now high-value candidates for future sterility research.
Gene Atlas
Their work bridges NOAA’s applied aquaculture mission and UW’s expertise in molluscan developmental genomics, resulting in the first single-cell molecular map of oyster development prior to the trochophore stage — a foundational resource for both aquaculture innovation and evolutionary developmental biology.
Single-cell transcriptional heterogeneity of early C. gigas embryos increases with developmental time. (A) Sampling design: cleavage-stage embryos were pooled into a single sample representing all cleavage stages. A sample of blastula-stage embryos were collected and sequenced in a separate library to allow the identification of the developmentally oldest cells in the pool. Gastrula-stage embryos sampled at 10 hpf for reference. (B) UMAP visualization of single-cell clustering of the cleavage (pre-blastula) + blastula stage (cb) that revealed 10 putative clusters. (C) UMAP visualization of single-cell clustering of the gastrula stage. Twenty-seven putative clusters representing broad cell types were resolved using UMAP clustering analysis (Cil, ciliated cells; Circ, circulatory system-related; Mes, undefined mesodermal derivatives; Mus, muscle-related; Neu, neuronal; PGC, primordial germ cell; SF, shell field; Un, undefined)
What Comes Next
This atlas now enables targeted functional studies of early germline pathways — the next step toward non-triploid sterility methods for sustainable shellfish aquaculture. The open-access dataset will also support comparative evo-devo research across molluscs and other invertebrates.
Source: Gavery, M.R., Vandepas, L.E., Saunders, L.M., Vadopalas, B., Luckenbach, J.A., Trapnell, C., & Roberts, S.B. (2025). Primordial germ cell specification and early developmental cell states in Pacific oyster. BMC Genomics 26:951.