Exchange of Incompatibility Factors between the Nuclei of a Dikaryon

Papazian, Haig P.

doi:10.1126/science.119.3098.691

Cited by 23 publications

(5 citation statements)

References 3 publications

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“…There is also much evidence from both Coprinus (Buller, 1931;Quintanilha, 1938;Swiezynski, 1962Swiezynski, , 1963 and the related fungus Schizophyllum commune (Papazian, 1954;Crowe, 1960;Ellingboe & Raper, 1962;Parag, 1962;Ellingboe, 1963) indicating somatic recombination in the dikaryon which suggests that diploid nuclei can be produced as a result of some kind of vegetative karyogamy. The technique of dikaryon-monokaryon matings (termed di-mon, Papazian, 1950), used by the majority of the above workers, selects for recombinant nuclei which may be haploid or aneuploid.…”

Section: Introductionmentioning

confidence: 94%

The production and behaviour of diploids ofCoprinus lagopus

Casselton¹

1965

Genet. Res.

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Diploid strains of Coprinus lagopus have been synthesized from common A heterokaryons either as oidial colonies or sectors. The criteria of growth rate and colony morphology on selective medium were used to distinguish between diploid and heterokaryon colonies. The average oidial size and hyphal width of diploid strains was significantly greater than that of the haploid parental strains.Diploid monokaryons were very stable and only rarely produced haploid segregants. However, aneuploid intermediates in haploidization have been identified and these segregated further to give haploid monokaryons with recombinant genomes.Dikaryons formed from diploid and haploid strains produced fruiting bodies. Meiosis and basidiospore production were irregular owing to the formation of triploid or partially triploid fusion nuclei in the basidia. In contrast to their stability in monokaryons, diploid nuclei tended to be unstable when combined in a dikaryon with a haploid nucleus, and often underwent partial haploidization before fruiting. Segregation of genes in the basidiospore progeny reflected whether haploidization had occurred before or after the formation of the fruiting body. If the haploid nucleus had a B mating-type allele common to the diploid nucleus, haploidization effected loss of the common allele.

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Section: Introductionmentioning

confidence: 94%

The production and behaviour of diploids ofCoprinus lagopus

Casselton¹

1965

Genet. Res.

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“…Each culture was markers (Papazian 1954;Crowe 1960;Parag 1962; serially transferred to a new petri dish every 2 weeks. Two 1964;Frankel 1979).…”

Section: Dikaryon-monokaryon Matingsmentioning

confidence: 99%

Dikaryons of the Basidiomycete Fungus Schizophyllum commune

Clark

Anderson

2004

Genetics

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The impact of ploidy on adaptation is a central issue in evolutionary biology. While many eukaryotic organisms exist as diploids, with two sets of gametic genomes residing in the same nucleus, most basidiomycete fungi exist as dikaryons in which the two genomes exist in separate nuclei that are physically paired and that divide in a coordinated manner during hyphal extension. To determine if haploid monokaryotic and dikaryotic mycelia adapt to novel environments under natural selection, we serially transferred replicate populations of each ploidy state on minimal medium for 18 months ‫000,31ف(‬ generations). Dikaryotic mycelia responded to selection with increases in growth rate, while haploid monokaryotic mycelia did not. To determine if the haploid components of the dikaryon adapt reciprocally to one another's presence over time, we recovered the intact haploid components of dikaryotic mycelia at different time points (without meiosis) and mated them with nuclei of different evolutionary histories. We found evidence for coadaptation between nuclei in one dikaryotic line, in which a dominant deleterious mutation in one nucleus was followed by a compensatory mutation in the other nucleus; the mutant nuclei that evolved together had the best overall fitness. In other lines, nuclei had equal or higher fitness when paired with nuclei of other histories, indicating a heterozygote advantage. To determine if genetic exchange occurs between the two nuclei of a dikaryon, we developed a 24-locus genotyping system based on single nucleotide polymorphisms to monitor somatic exchange. We observed genetic exchange and recombination between the nuclei of several different dikaryons, resulting in genotypic variation in these mitotic cell lineages.

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“…It is the most complicated pattern of sexuality known among fungi (Raper and Flexer 1971). Studies on Schizophyllum commune have revealed that each compatibility factor represents two c1osely-linked genes designated 'a' and '~' (Papazian 1954, Raper et al 1958. This two gene structure has also been demonstrated in Pleurotus ostreatus (Terakawa 1957(Terakawa , 1960, Collybia velutipes (Takemaru 1961) and Coprinus lagopus (Day 1963), and is considered to hold true for all tetrapolar forms.…”

Section: Homothaliism and Heterothaliismmentioning

confidence: 88%