Linkage of conidial longevity determinant genes in Neurospora crassa

The longevity of conidia of Neurospora crassa was previously defined as their ability to grow after aging in a constant environment. The heritable median lifespan of the wild type is 22 days. Heritable mutants with lifespans of 5-7 days were previously selected. The pleiotropic colony phenotype of the mutants greatly facilitates genetical analysis of their inheritance. Twenty-eight mutants were mapped by recombinational analysis. All but one were located at genes on one arm of the seven chromosomes, linkage group IR; the exception was at the terminus of linkage group VIR. Sixteen of the 17 genes on IR are collectively called the age-1 complex. The average and standard deviation of the distance of 13 intervals between adjacent genes in the complex was 4.9 +/- 1.1 map units; hence they appear to be spatially reiterated. Other observations indicate that the genes are also functionally redundant.