Studies on genetic organization in higher organisms. II. Complementation and fine structure of the maroon-like locus of Drosophila melanogaster.

Mutants of the maroon-like complex, representative of the five known complementation classes, were subjected to fine structure mapping experiments utilizing a nutritional selective procedure which permits the survival of rare ma-l(+) progeny from large-scale crosses. The analysis provides an internally consistent, unique map, colinear with the complementation map. Noncomplementers exhibit a polarized mapping distribution. In addition to ma-l(+) recombinants, the selective medium permitted the survival of ma-l(+) exceptionals not associated with recombination for adjacent markers. Analysis of the exceptionals favors their origin as convertants.