Genetic sex reversal of rainbow trout

A majority of rainbow trout produced in the US are derived from all-female stocks due to improved harvest traits and efficiency over mixed sex stocks. The development of all-female stocks currently relies on the use of the testosterone derivative 17 & #945; & #8722;methyltestosterone, however the long term use of this method is not guaranteed as regulations governing the use of the substance are becoming more stringent. Troutlodge Inc. in cooperation with researchers at Washington State University, has isolated rare XX individuals that develop as functional males. The sex ratio of progeny produced by these rare individuals indicates an autosomal recessive mutation causing the maleness. We will test the feasibility and functionality of using these individuals as a new method of production of all female lines without the use of hormones. Fine mapping in an attempt to identify the specific sex-reversal locus would occur in Phase II of the grant.