Determining Sex in Xenopus laevis Tadpoles

Xenopus laevis has a ZZ/ZW type sex determination system, and a PCR-based method was developed in 2007 to distinguish ZZ males from ZW females. As X. laevis can regenerate tail tissue as tadpoles, this method can be used to determine sex from DNA extracted from tadpole tail clips, which enables accurate identification of sex. Male X. laevis reach sexual maturity faster than females, so we routinely select male tadpoles for establishing transgenic lines. It may also be useful to stratify behavioral or drug testing results by biological sex. Here, I present a quick and simple multiplex PCR-based method for isolating genomic DNA and using this to determine biological sex, based on the presence or absence of the female specific gene dm-W. Females are identified by the presence of two bands and males by a single band.