medaka

Wittbrodt J, Shima A & Schartl M 2002 Medaka — a model organism from the Far East. Nat Rev Genet 3:53-64.

• nothing is known about sex determination in zebrafish
• none of the many markers of the zebrafish genetic map have been found to be sex linked
• medaka has clearly defined sex chromosomes

• medaka was an important test system for environmental research
• it is widely used for carcinogenesis studies²⁹ and for testing endocrine disruptors in ecotoxicology