CRISPR/Cas9-Mediated Loss of FGF5 Function Increases Wool Staple Length in Sheep

The study demonstrated that CRISPR/Cas9-mediated disruption of the FGF5 gene in Chinese Merino fine wool sheep significantly increased wool staple length and yield without affecting wool fineness. Sixteen genetically modified lambs were produced, with 12 surviving for over a year. These lambs exhibited longer wool staple lengths (10.73 cm vs. 9.23 cm) and stretched lengths (12.29 cm vs. 10.86 cm) compared to controls, along with a significant increase in greasy fleece weight (3.74 kg vs. 2.96 kg). The predominant gene modifications led to non-functional FGF5 proteins, removing its inhibitory effect on wool growth, thereby enhancing wool production.