FRT 42D and ovo
D
– Using a New Genetic Tool for a Large Scale Maternal Effect
Screen in Drosophila melanogaster
Ernesto Lujan
Mentor: Rahul Warrior
One method of analyzing gene function is to examine phenotypes of tissues that are homozygous mutant for the gene of interest. A problem with this approach is that the wild-type gene product is often essential for the organism to develop to a stage where the tissue can be examined. A solution is to generate clones of homozygous mutant cells in animals that are otherwise heterozygous. Clones are generated by first recombining a mutation onto a chromosome that contains a Flippase Recombination Target (FRT) sequence. Expression of the Flippase (FLP) enzyme in animals heterozygous for the chromosome and a wild-type FRT chromosome results in recombination and daughter cells that are either homozygous for the mutation or for the wild-type chromosome. This is particularly useful when analyzing the maternal effect of homozygous lethal mutations in Drosophila melanogaster , as female germline cells can be made homozygous for the mutation while somatic cells are heterozygous for the mutation, and thus the organism is viable. For easy selection of germline clones, the dominant female sterile mutation, ovo
D
, is used, as only recombined cells that are homozygous for the mutation develop successfully. Currently, a chromosome with FRT 42D and ovo
D
is not available. We have created this chromosome and are using it to analyze the maternal effect phenotype of 237
P-transposable element induced lethal mutations from the Drosophila Stock Center at
Bloomington, Indiana that were each recombined onto chromosomes with FRT 42D.