noun
: a genetic process that is sometimes associated with meiotic recombination in heterozygotes if heteroduplex DNA is formed, that involves the selective enzymatic excision of a mismatched DNA sequence from one heteroduplex strand and replacement with a nucleotide sequence complementary to the other strand so that the two DNA strands are genetically identical, that results in aberrant gametic ratios, and that is observed experimentally especially in ascomycetous fungi (as of the genera Saccharomyces, Neurospora , or Aspergillus ) in which the products of a single meiotic event are retained in one ascus