Abstract
Organoids are three-dimensional structures that develop in cultures of stem cells, and resemble multicellular organs. While performing long-term culture of Taeniopygia guttata (zebra finch) germline tissue, we observed the formation of germline organoids from cultures of both sexes. These macro-scale structures contain multiple cell types and retain Primordial Germ Cells (PGCs) and their descendant germ-cell lineages for two to four months of culture in vitro. We show that the PGC-specific germline-restricted chromosome (GRC) can be detected after three months of culture, and that the organoids exhibit DAZL- and DDX4-positive structures resembling germinal epithelia. Taken together our results open new possibilities for the study of key steps of avian reproductive development.
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Data availability
Data generated in this study is available by contacting the corresponding author, John Bracht (jbracht@american.edu).
Code availability
All code, documentation, and related genomic data are available in GitHub page of the Bracht lab, “PGC-Organoid-Tracking” https://github.com/brachtlab/PGC-Organoid-Tracking
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Acknowledgements
We acknowledge NIH grant 1R15GM146207 to J.R.B. and our anonymous reviewers for their feedback. We also acknowledge the technical help provided by Dr. Erich Jarvis and his laboratory especially including Dr. Anna Keyte who taught us how to dissect embryos, and Dr. Matthew Biegler. We also appreciate the Rockefeller group’s sharing of a PCR sex-determination protocol with optimized primers. We also acknowledge the generous donation of the anti-Aromatase antibody, AZAC, and finch testis tissue, from Dr. Colin Saldanha, as well as his financial support of the project.
Funding
The work was supported by NIH grant 1R15GM146207 to J.R.B. and NSF grant 2050260 to Colin Saldanha.
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Bianca Brown performed supervision, project administration, investigation, and writing-first draft. Elizabeth Nagy performed investigation, visualization, and writing-first draft. Ajuni Takkar performed investigation and writing-first draft. Naomi Greengold performed investigation. Shreyas Gujar performed investigation, methodology, data curation, writing-first draft and writing-editing. Ali Amini performed formal analysis, visualization, software, conceptualization, investigation, writing-first draft, and writing-editing. Mary Collins performed investigation, visualization, methodology, and writing-first draft. Javad Rajabi performed formal analysis, software, and methodology. Jenna Walls performed investigation. Chenai Kaminski performed investigation, visualization, and formal analysis. Michael Sanchez performed investigation and writing-first draft. Elle Guzman performed investigation and writing-first draft. Tarraji Ellington performed investigation and writing-first draft. John Bracht performed conceptualization, visualization, formal analysis, software, investigation, funding acquisition, supervision, project administration, and writing-review and editing.
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Brown, B., Nagy, E., Takkar, A.K. et al. Germline organoids develop in vitro from embryonic Taeniopygia guttata (zebra finch) cultures. Sci Rep (2026). https://doi.org/10.1038/s41598-026-46600-z
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DOI: https://doi.org/10.1038/s41598-026-46600-z
