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EDCAT 7: Roach Reproduction

This project will determine whether or not "feminized" roach Rutilus rutilus from the Ray and elsewhere can reproduce, and if so, how successful they are when they spawn together with other fish in shoals.  Groups of roach (representative of a naturally spawning shoal), containing both normal and "feminized" fish, will be allowed to spawn naturally in large fish tanks. 

The eggs will be allowed to develop without interference, and the offspring grown under as natural conditions as possible.  Once the young are large enough, genetic fingerprinting techniques will be used to assign the offspring to the adults (the parents).  In this way we will discover which adults contributed to the next generation (the offspring), and to what degree. We need only for the embryos to be large enough for genotyping.  We will probably grow them to first exogenous feeding, or thereabouts. 

By genotyping both adults and offspring (embryos), we will find out whether or not "feminized" fish can reproduce, and if so, how successfully compared with normal fish.  This information will enable us to deduce whether or not "feminization" of male fish poses a threat to the long-term sustainability of fish populations.

The roach Rutilus rutilus

		Towards an undertstanding of the ability of interersex roach to sire offspring in a breeding population.
What are DNA microsats? Tandemly arrayed  non-coding sequences. Allelic variations of microsats are co-dominant and show Mendelian inheritance. Microsatellite loci often have many alleles and show high heterozygosity, so parentage may be ascertained unambiguously using a few microsat markers.

Objectives:

1. Develop a suite of DNA microsatellite markers that can be used to assign parentage to roach: Months 1-12
2. Determine to what degree endocrine disrupted male roach can contribute to the next generation when they spawn together with normal male fish: Months 12-24
3. Assess how the ratio of endocrine disrupted to normal male fish affects the reproductive performance of the disrupted male fish: Months 24-36
4. Assess how the degree of competition for females affects the reproductive performance of endocrine disrupted male fish: Months 24-36.

Project Leader:

Professor John Sumpter	Professor Charles Tyler	Dr Susan Jobling	Dr Catherine Harris

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