Determining the role of patterned cell proliferation in the shape and size of the Drosophila wing.

The present work is a detailed analysis of the numerical and positional parameters of cell proliferation in all of the derivatives of the wing disk. We have made use of twin clones resulting from mitotic recombination events at three different ages of development. The interfaces between twin clones indicate the relative position in the anlage of the mother cells. Interface types vary with age of clone initiation and with wing regions. They are indicative of the main allocation of postmitotic cells of the growing clones. Growth is exponential and intercalar, i.e., the progeny of ancestor cells becomes more and more separated. Clones are compact, indicating that daughter cells tend to remain side by side. The shape of the clones is wing region characteristic. Subpopulations of cells grow preferentially along veins and wing margins and show characteristic shapes in different pleural regions. The shape and size of the adult wing regions largely depend on the shape of clones and hence of the allocation of successive rounds of daughter cells. The role of mitogenic morphogens in wing size and shape is discussed.