The developmental study of the wing disc in Drosophila has revealed the progressive appearance of heterogeneities in the anlage formation i.e., of symmetric compartments, of lineage restrictions for vein and intervein regions within compartments, and in mitotic waves. The genetic analysis of alleles in 28 loci that affect vein formation allows us to classify them, according to their phenotypic effects in mutant combinations, in several groups of synergism. These effects include changes in vein differentiation, vein pattern, and growth of the wing anlage. Clonal analyses of mutations of these groups shows that pattern differentiation is associated with changes in cell proliferation dynamics. The study of combinations of mutations from different groups allows us to infer the existence of distinct genetic operations in wing development. A model is presented relating these genetic operations to cell proliferation and cell communication in wing morphogenesis and vein patterning.Key words: pattern formation, morphogenesis, cell proliferation and differentiation.