Adaptation in Pantothenate ‐ Requiring Neurospora. I. A Gene Modifying Pantothenate Mutants

D avis, r . H. (California Inst. Tech., Pasadena.) Adaptation in pantothenate‐requiring Neurospora. i. a gene modifying pantothenate mutants. Amer. Jour. Bot. 4(5): 351–357. Illus. 1960.—a modified pantothenicless strain was isolated from a pan‐1, al‐1, A mycelium which had adapted to a limiting concentration of pantothenate. The modified and original strains differ by a single gene, m, which is not linked genetically to either of the 2 known pantothenic acid loci. The gene m appears to modify the uptake, rather than the synthesis, of pantothenate on the part of both pan‐1 and pan‐2 mutants. Neither pan mutant in combination with m grows on minimal medium. However, the pan‐1 m and pan‐2 m strains grow to a greater extent than pan‐1 or pan‐2 in limiting pantothenate concentrations. The mechanism of action of the m gene is discussed, and compared to modifiers of certain other mutant phenotypes of Neurospora .