Related Experiment Video
Updated: Aug 5, 2026

Genetic Manipulation of the Plant Pathogen Ustilago maydis to Study Fungal Biology and Plant Microbe Interactions
Published on: September 30, 2016
Genes in Neurospora that suppress recombination when they are heterozygous
Abstract:
Genes that suppress recombination when heterozygous have been found distributed as a polymorphism in wild and laboratory populations of Neurospora crassa. Three alleles, ssE, ssS and ssC, are associated, respectively, with th the three wild types Emerson, St. Lawrence 74A and Costa Rica A. It is proposed that ss (synaptic sequence) genes modulate recombination by determining the pairing closeness of DNA duplexes in the vicinity of the nit-2 locus. When heterozygous, ss suppresses recombination 2- to 20-fold within the nit-2 locus, which it adjoins, but crossing over in intervals flanking nit-2 is not affected. The magnitude of suppression depends upon the ss alleles involved, and ss acts multiplicatively with rec-1; together, these genes modulate recombination within the nit-2 locus over a range exceeding 100-fold. The ss effect is not attributable to gross chromosomal rearrangement, but could be due to small inversions or insertions, such as transposable elements.
Related Concept Videos
In-vitro Mutagenesis
Law of Segregation
Position-effect Variegation
Gene Conversion
Incomplete Dominance
Gene Regulation During Sporulation

