The genetic basis for the meiotic disorder of Coprinus congregatus

Area of Science:

• Mycology
• Genetics
• Cell Biology

Background:

• A "pale-mushroom" phenotype in *Coprinus congregatus* was previously attributed to a cytoplasmic infectious agent inhibiting synaptonemal complex formation.
• This infectivity was successfully maintained for 5 years via material extraction from carrier homokaryons.

Purpose of the Study:

• To investigate the genetic basis of the pale-mushroom phenotype in *Coprinus congregatus*.
• To understand the shift from apparent cytoplasmic inheritance to nuclear control.

Main Methods:

• Genetic analysis of *Coprinus congregatus*.
• Phenotypic observation of homokaryotic and dikaryotic fungal cultures.
• Somatic fusion experiments to assess cytoplasmic transmission.

Main Results:

• The pale-mushroom phenotype is primarily determined by a nuclear gene, symbolized as *pal* (-).
• The pale phenotype manifests predictably in dikaryons that are homoallelic for the *pal* (-) allele.
• Homoallelic wild type (*pal* (+)) and heteroallelic dikaryons exhibit the normal dark phenotype.

Conclusions:

• The pale-mushroom phenotype in *Coprinus congregatus* is predominantly governed by nuclear gene *pal*.
• The loss of previously observed cytoplasmic infectivity suggests a complex inheritance pattern, potentially involving both nuclear and cytoplasmic factors under specific conditions.