Genetic analysis of a cross between two homothallic strains of Physarum polycephalum

SUMMARYThe homothallic amoebal clones of Physarum polycephalum are of potential use in understanding the developmental genetics of this organism. Such an application requires that complementation and recombination analysis be possible between pairs of homothallic clones. This paper is a report of the formation of mixed plasmodia by pairs of homothallic amoebal clones. In order to detect such mixed plasmodia use was made of two marker genes involved in plasmodial fusion, fusA and fusB. Sporulation of a mixed plasmodium formed from two homothallic (delayed) amoebal clones yielded progeny amoebae which were genetically recombinant. It is deduced from the ratios of various genotypes in these progeny clones that the mixed plasmodium was diploid and that meiosis was associated with sporulation. There is therefore no impediment to the use of the homothallic strains for genetical analysis. The progeny amoebal clones were observed to be showing segregation for the characters homothallic (rapid) and homothallic (delayed). This observation, taken together with other related observations, suggests that the homothallic (delayed) character is produced by mutation of the homothallic (rapid) character. The rare plasmodia formed by a homothallic (delayed) amoebal clone are the result of reversion of this mutation. Amoebal clones of the homothallic (delayed) type are therefore developmental mutants unable to perform the differentiation from amoeba to plasmodium.

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Developmental mutants in a homothallic strain of Physarum polycephalum

Genetics Research ◽

10.1017/s0016672300013239 ◽

1973 ◽

Vol 21 (1) ◽

pp. 79-86 ◽

Cited By ~ 25

Author(s):

A. E. Wheals

Keyword(s):

Synergistic Effect ◽

Ultraviolet Light ◽

Mating Type ◽

Physarum Polycephalum ◽

High Efficiency ◽

Type A ◽

Wild Type ◽

Developmental Transition ◽

Developmental Mutants

SUMMARYA derivative line of the homothallic Colonia strain of Physarum polycephalum has been isolated which produces plasmodia with high efficiency within clones of amoebae. Using the synergistic effect of ultraviolet light and caffeine, mutants of this line have been isolated which fail to undergo the developmental transition between haploid amoebae and diploid plasmodia (apt mutants). They are isolated by selecting for amoebae which fail to produce plasmodia within clones. Complementation tests of four mutants have shown that they are mutants of four different loci and they are recessive to wild-type. A further analysis of one mutant reveals that the apt-1 locus is unlinked to three other known markers. Crosses of this mutant with heterothallic strains yield progeny which are homothallic indicating that the lesion is not a revertant from a homothallic to a heterothallic mating-type. The use of this system in isolating developmental mutants is discussed.

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Genetic analysis of a potato (Solanum tuberosum L.) breeding collection for southern Colombia using Single Nucleotide Polymorphism (SNP) markers

PLoS ONE ◽

10.1371/journal.pone.0248787 ◽

2021 ◽

Vol 16 (3) ◽

pp. e0248787

Author(s):

Jhon A. Berdugo-Cely ◽

Carolina Martínez-Moncayo ◽

Tulio César Lagos-Burbano

Keyword(s):

Linkage Disequilibrium ◽

Genetic Analysis ◽

Solanum Tuberosum L ◽

Genetic Distances ◽

Snp Markers ◽

Detailed Knowledge ◽

Nucleotide Polymorphisms ◽

Single Nucleotide ◽

Genetic Breeding ◽

Potential Use

Detailed knowledge on genetic parameters such as diversity, structure, and linkage disequilibrium (LD) and identification of duplicates in a germplasm bank and/or breeding collection are essential to conservation and breeding strategies in any crop. Therefore, the potato genetic breeding collection at the Universidad de Nariño in Colombia, which is made up of diploid and tetraploid genotypes in two of the more diverse genebanks in the world, was analyzed with 8303 single nucleotide polymorphisms (SNP) from SolCAP version 1. In total, 144 genotypes from this collection were analyzed identifying an 57.2% of the polymorphic markers that allowed establishing two and three subpopulations that differentiated the diploid genotypes from the tetraploids. These subpopulations had high levels of heterozygosity and linkage disequilibrium. The diversity levels were higher in the tetraploid genotypes, while the LD levels were higher in the diploid genotypes. For the tetraploids, the genotypes from Peru had greater diversity and lower linkage disequilibrium than those from Colombia, which had slightly lower diversity and higher degrees of LD. The genetic analysis identified, adjusted and/or selected diploid and tetraploid genotypes under the following characteristics: 1) errors in classification associated with the level of ploidy; 2) presence of duplicates; and 3) genotypes with broad genetic distances and potential use in controlled hybridization processes. These analyses suggested that the potato genetic breeding collection at the Universidad de Nariño has a genetic base with a potential use in breeding programs for this crop in the Department of Nariño, in southern Colombia.

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A NEW MATING COMPATIBILITY LOCUS IN PHYSARUM POLYCEPHALUM

Genetics ◽

10.1093/genetics/91.4.683 ◽

1979 ◽

Vol 91 (4) ◽

pp. 683-693

Author(s):

Philip J Youngman ◽

Dominick J Pallotta ◽

Betsy Hosler ◽

Gary Struhl ◽

Charles E Holt

Keyword(s):

Genetic Analysis ◽

Mating Type ◽

Physarum Polycephalum ◽

Type Locus ◽

Mating Type Locus ◽

Mating Compatibility ◽

Mating Efficiency ◽

Mating Tests ◽

Specificity System

ABSTRACT The rate and extent of plasmodium formation were studied in mating tests involving pairs of largely isogenic amoeba1 strains compatible for matingtype (mt) alleles. A systematic variability was observed: plasmodia formed either rapidly and extensively or slowly and inefficiently. Plasmodium formation was found to be 103- to 104-fold more extensive in "rapid" crosses than in "slow" crosses. A genetic analysis revealed that the variability reflects the influence of a multiallelic compatibility locus that determines mating efficiency. This compatibility locus (designated matB), together with the original mating type locus mt (in this work designated matA), constitute a tetrapolar mating specificity system in Physarum polycephalum.

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Genetic analysis of anther-derived plants of rice: independent assortment of unlinked genes

Canadian Journal of Genetics and Cytology ◽

10.1139/g83-051 ◽

1983 ◽

Vol 25 (4) ◽

pp. 324-328 ◽

Cited By ~ 16

Author(s):

C. C. Chen ◽

W. L. Chiu ◽

L. J. Yu ◽

S. S. Ren ◽

W. J. Yu ◽

...

Keyword(s):

Oryza Sativa ◽

Genetic Analysis ◽

Indirect Evidence ◽

Marker Genes ◽

Haploid Cell ◽

Diploid Plant ◽

Chi Square ◽

Independent Assortment ◽

Progeny Tests ◽

Waxy Locus

Haploid and diploid plants produced from anther culture of two hybrids of rice (Oryza sativa), each heterozygous for two unlinked genes, were subjected to genetic analysis. Progeny tests showed that all diploids but one were homozygous for both loci. Chi-square tests of the haploids and homozygous diploids revealed that the two genes in each hybrid segregated in the expected 1:1 ratio and that the four genotypic classes fit a 1:1:1:1 ratio, indicating that independent assortment of marker genes occurred and that the gametes were equally viable in the microspore-derived progeny. One diploid plant produced from anthers of the hybrid of genotype wx+wx lg+lg was found to be homozygous for lg+ but heterozygous for the waxy locus. Indirect evidence suggests that a mutation at the waxy locus in a spontaneously doubled haploid cell during culture may be the cause for occurrence of this unusual plant.

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Plasmodial Fusion in Physarum Polycephalum: Genetic Analysis of a Turtox Strain

Mycologia ◽

10.1080/00275514.1972.12019357 ◽

1972 ◽

Vol 64 (5) ◽

pp. 1130-1137 ◽

Cited By ~ 5

Author(s):

O'Neil Ray Collins

Keyword(s):

Genetic Analysis ◽

Physarum Polycephalum

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Methods for the isolation and analysis of plasmodial mutants in Physarum polycephalum

Genetics Research ◽

10.1017/s0016672300015202 ◽

1974 ◽

Vol 24 (2) ◽

pp. 175-187 ◽

Cited By ~ 67

Author(s):

D. J. Cooke ◽

Jennifer Dee

Keyword(s):

Life Cycle ◽

Genetic Analysis ◽

Genetic Background ◽

Physarum Polycephalum ◽

High Efficiency ◽

Single Gene ◽

Gene Mutations ◽

Auxotrophic Mutants

SUMMARYAmoebae of the Colonia isolate of Physarum polycephalum produce plasmodia within individual amoebal clones.This paper reports the derivation from the Colonia strain C50 of a strain CL (Colonia Leicester) which produces plasmodia in clones with high efficiency and which completes the life cycle reliably and repeatedly in single clones. The derivation of a line CLd (CL delayed plasmodium formation) is described and, using CLd, the construction of the isogenic heterothallic strains mt1; CL and mt2; CL.The above strains provide a system for the isolation and genetic analysis of mutants of P. polycephalum within a uniform genetic background, in particular mutants expressed in the plasmodium.Using this system two auxotrophic mutants have been isolated. Preliminary genetic analysis has shown that they are due to single gene mutations.

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