Fig. 7

Genetic manipulation techniques. A–C Over the last two decades, techniques such as Tol2 transgenesis and CRISPR–Cas9 genome editing have been successfully adapted in cichlid fishes. A challenge compared to traditional model teleost fishes (such as zebrafish and medaka) is the small number of eggs per clutch (usually 15–50 eggs), the oval egg shape, and the difficulty in timing fertilization. As in zebrafish, eggs are microinjected using an air pressure-driven microinjector (A). Eggs can be held with forceps or put into a supporting agarose mold (B). After microinjection, eggs are kept individually in well plates until larvae are free swimming (C). Photo credits: Bettina Fischer (B)