FUNCTIONAL REDUNDANCY - THE RESPECTIVE ROLES OF THE 2 SLOPPY PAIRED GENES IN DROSOPHILA SEGMENTATION

The sloppy paired (slp) locus consists of two genes, slp1 and slp2, bo th of which encode proteins containing a forkhead domain (a DNA-bindin g moth). Previous work has shown that a severe segmentation phenotype is obtained only when both slp genes are deleted. Here we examine the functional redundancy of the locus in more detail. The phenotypes of e mbryos containing various combinations of functional slp genes suggest that for early slp function, until gastrulation, only slp1 is require d. At later times, there is still a greater requirement for slp1, but in many respects the two slp genes are completely redundant. Both slp genes produce similar phenotypes when ubiquitously expressed via a hea t shock promoter. We propose that the slp proteins are biochemically e quivalent and that the greater requirement for slp1 in some functions can be explained in large part by its earlier expression.