Genome editing in chickens

Chicken (Gallus gallus) is a major protein source and an important model organism in the avian species. Although genome editing has enabled genetic modifications of various organisms and has a significant impact on academia and industry, its application to chickens has been comparatively delayed owing to difficulties in handling their one-cell fertilized eggs. Thus, researchers have attempted to produce genome-edited chickens using primordial germ cells (PGCs), which are precursor cells of sperm or eggs. Currently, genome-edited chickens can be produced with the development of avian biotechnologies, PGCs culture methods, and germline chimerism systems, in particular. In this review, we describe the current status of genome editing in chickens, including avian biotechnologies, with a primary focus on the achievements of Japanese researchers. In addition, we discuss the remaining issues and make suggestions for future research.