OBJECTIVE OF THE EXPERIMENT The goal of these experiments is to study the effects on cell proliferation and vein patterning caused by mutations in theemc gene during development of the imaginal wing discs. To this end, two different experiments will be performed:

1. Twin analysis. Clones ofemc mutant cells will be generated by mitotic recombination at the same time that “twin” clones are generated that are emc+ (control). With this experiment we will be able to analyse the difference in size (number of cells), shape and distribution ofemc mutant clones in comparison to control twins.

2. Minute analysis.emc1M+/emc1M+ mutant cells will be induced in aM−/M+ mutant background. In aM−/M+ heterozygous backgroundM+/M+ cells exhibit a growth advantage that allows clones initiated early in development to occupy large wing territories. This experiment, which supports the notion that size control is not based on cell proliferation rate control, will allow us to study the effects caused by the presence of a large region ofemc mutant cells in the growing wing.

DEGREE OF DIFFICULTY Moderate.

INTRODUCTION

The development of the imaginal wing discs ofDrosophila melanogaster is a classic model system for analysis of the cellular and genetic bases of cell proliferation and pattern formation. Each wing disc gives rise to one wing and one-half of the adult thorax. These discs arise from a group of 20–40 cells that are segregated from the embryonic cells during early embryogenesis. These founder cells proliferate extensively during the larval stages until the beginning of metamorphosis.