RECOVERY OF DUPLICATIONS BY DRUG-RESISTANCE SELECTION IN CAENORHABDITIS-ELEGANS

We have devised a scheme that facilitates rapid screening for duplicat ions of essential loci. Our scheme takes advantage of the lev-1(x22) m utation, which confers resistance in a recessive fashion to the potent anthelmintic levamisole. We have tested our methodology by recovering two gamma ray induced duplications of let-56, the first essential gen e to the left of unc-22. One of the duplications is attached to the fo urth chromosome. The other duplication is attached to the X chromosome . This duplication contains a functional copy of the unc-22 gene, as w ell as functional copies of several essential loci adjacent to unc-22. Results we have obtained during analysis of this duplication are comp atible with the notion that the copy of the unc-22 gene located on the duplication is subject to X chromosome dosage compensation.