Open AccessGenetic analysis of a suppressor of urease‐deficiency in Neurospora crassa
Author(s) -
BUREMALM KERSTIN E.,
KØLMARK H. GUNNAR
Publication year - 1971
Publication title -
hereditas
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 50
eISSN - 1601-5223
pISSN - 0018-0661
DOI - 10.1111/j.1601-5223.1971.tb02440.x
Subject(s) - neurospora crassa , biology , suppressor , mutant , genetics , offspring , locus (genetics) , neurospora , urease , genetic analysis , complementation , gene , enzyme , biochemistry , pregnancy
The urease‐deficient mutants ure‐1 (9) and ure‐2 (47) of Neurospora crassa are previously known to be closely linked. In a certain cross between these mutants an unexpectedly high frequency of urease‐positive offspring was found. In further analysis, making use of closely linked markers and isolating ascospores by linear dissection, it was disclosed that the deviating results could be explained by the presence of a suppressor, henceforth named su [ ure‐1 (9)], which specifically acts to annul the urease‐deficient phenotype of ure‐1 (9). The suppressor appears to be unlinked to the suppressed mutant locus. The suppressor action is reproduced in parent‐offspring crosses and in crosses between the spore pairs in segregating asci, but no such action has so far been found outside the family where it was first discovered. The total evidence is interpreted to mean that suppression of ure‐1 (9) proceeds with the interaction of two genetic entities: An unlinked suppressor and a hypothetical “co‐suppressor”, which is linked to the ure‐1 locus. Some examples are presented of ascus analysis when urease‐positive offspring appear simultaneously by recombination between the urease‐mutant loci and by suppression of one of these.