Generation of Chimera-Competent Avian iPSCs Using Defined Transcription Factors

iPSC technology is well established in mammals but remains underdeveloped in non-mammalian species. A major barrier to generating avian iPSCs has been the lack of species-specific reprogramming factors and culture conditions capable of supporting self-renewal in avian pluripotent stem cells. Here, we report the generation of chicken iPSCs (ciPSCs) using a cocktail of seven chicken transcription factors (T7: Oct4, Sox2, Sox3, Klf4, c-Myc, Nanog, and Lin28B) combined with an optimized avian culture system. Transcriptomic and functional analyses identified Sox3, rather than Sox2, as the predominant SoxB1 factor in avian reprogramming. The resulting ciPSCs exhibited stable self-renewal for over 40 passages, expressed core pluripotency markers, differentiated into all three germ layers, and were transcriptionally similar to chicken ESCs. In chimera assays, ciPSCs contributed to somatic, extra-embryonic, and germline lineages, giving rise to gonadal PGC-like cells that did not acquire full germline competence. We further demonstrate that the T7 system generates iPSCs from quail, duck, peacock, zebra finch, and pigeon, and that duck iPSCs can form interspecies chimeras with donor cells detected in the host gonads. These findings establish a generalizable platform for avian iPSC generation with applications in developmental biology and germline preservation of endangered species.