Arginine pathway

Arginine dihybrid abArginine dihybrid bc

Recessive epistasis in the diploid Arginine biosynthesis pathway: dihybrid crosses

    Beadle & Tatum analyzed the genetics of Arginine biosynthesis in the haploid bread mold Neurospora. The same pathway occurs in diploid organisms: genetic analysis of mutant alleles affecting metabolic intermediates of Arginine production provides a general model for the behavior of multiple gene loci in a single pathway.

Homework: The Punnet squares show the enzymatic [colour] and growth [+ or -] phenotypes of two crosses between two dihybrid auxotrophic mutants Assume
dominance of the wild-type allele at each locus (x+). What general principles can be drawn from the patterns, as related to tri-hybrid crosses, and other forms of gene interactions in metabolic pathways?

All text material ©2014 by Steven M. Carr