Intragenic recombination at the white locus of Drosophila hydei.

A fine-structure analysis of the white locus in Drosophila hydei was carried out by means of allele recombination. Four mutants, derived from wild type, mapped at three subloci. These are possibly homologous to the main subloci 2, 3, and 4 of D. melanogaster. Three secondary mutants, derived from the primary wiv allele, were located in the proximal part of the gene. One of them appeared as a homoallele of the original wiv, whereas the remaining two are better explained either as double mutants or as mutants which facilitate irregular exchange. Intragenic recombination at the white locus seems to be more frequent in D. hydei than in D. melanogaster. The comparatively high incidence is probably a general characteristic, common to intragenic and intergenic recombination in D. hydei.