Occurrence in Wild Strains of Neurospora crassa of Genes Controlling Genetic Recombination

Abstract

Each of the main laboratory wild stocks of N. erassa carries one of two alleles at the ree-l and ree-2 loci and one of three at the ree-3 locus. The constitutions of the stocks are given in Fig. 1. Some of those conserved are evidently not the originals. The third ree-3 gene (ree-3L ), found in Lindegren A, controls recombination at the am-l locus to a level between that of ree-3+ and ree-3, the relative levels being 1 : 8 : 25. At the his-210cus ree-3L is indistinguishable from ree-3+ in its level of control. This proves that there are minor differences between the control (con) genes, near to am-l and his-2, which recognize products of ree-3 genes. Further, this is the first clear evidence, though indirect, that the binding sites for products of ree genes are situated in the chromosome regions where recombination is modulated.