Figure 1. Brief introduction of FCG mice. (A) Totally four genotypes of mice are produced by mating XXF to XYM mouse. XXF/XYF mice are gonadally females and XXM/XYM are males; among them, only XXF and XYM are fertile. (B) PCR results of FCG mice. MYO, autosomal gene (myosin) to confirm that PCR works (~250bp); YMT, Y gene to confirm presence of Y chromosome (~350bp); SRY, sex-determining region Y gene (~420bp).