Phycomyces: a new gene for a flavoprotein with covalently linked cofactor

We have identified a new locus in Phycomyces blakesleeanus that codes for a flavoprotein designated previously as FP₂. According to results from a sexual cross, this locus, flp, maps near the gene madC, a marker for abnormal phototropic sensitivity. The recombination frequency between flp and madC is about 10%. Further, the flp marker is unlinked with the carotene locus carA. Because the flavoprotein FP₂ is absent in certain photoreceptor mutants (Pollock et al. 1985 a), it had been proposed as a candidate for the blue-light photoreceptor. We have found, however, that some strains lacking this protein retain normal phototropism. Therefore, the flavoprotein FP₂ is probably not involved in photoreception.