Hello Nadine, Sex-limited genes are genes that are present in both sexes of sexually reproducing species but are expressed in only one sex and remain 'turned off' in the other. In other words, sex-limited genes cause the two sexes to show different traits or phenotypes, despite having the same genotype. As far as I know, to identify, say, the female organ suppressed gene in male flowers of Silene latifolia, you have to look for genes potentially involved in the establishment of floral organ and whorl boundaries. See the attached documents for detail, please.