Genetic analysis of the actinomycin-producing determinants (plasmid) in Streptomyces parvulus using the protoplast fusion technique

Doubly auxotrophic, actinomycin-producing and nonproducing strains of Streptomyces parvulus were crossed by protoplast fusion. A strong bias toward the act+ character was noted in all recombinant classes obtained. Analysis of four nutritonal markers revealed that they are ordered on a circular linkage map as follows: ura-lys-met-rib-(ura). This sequence resulted in the lowest frequency (2.4–3.4%) of quadruple crossover (QCO) recombinants. Inclusion of the property of actinomycin production in this sequence resulted in a much greater minimum frequency of QCO recombinants (3–4 times higher). Moreover, the location of the act character minimizing the QCO frequency varied from cross to cross despite the fact that fusion of the act− strains did not yield act+ recombinants. It is concluded that actinomycin synthesis is determined (or controlled) by an episomic factor(s).

Download Full-text

THE SELECTION OF S. CEREVISIAE MUTANTS DEFECTIVE IN THE START EVENT OF CELL DIVISION

Genetics ◽

10.1093/genetics/95.3.561 ◽

1980 ◽

Vol 95 (3) ◽

pp. 561-577 ◽

Cited By ~ 4

Author(s):

Steven I Reed

Keyword(s):

Cell Division ◽

Genetic Analysis ◽

Linkage Map ◽

Nuclear Genes ◽

Temperature Sensitive ◽

Restrictive Temperature ◽

Mating Pheromone ◽

Preliminary Characterization ◽

Complementation Groups ◽

Selection Of

ABSTRACT Thirty-three temperature-sensitive mutations defective in the start event of the cell division cycle of Saccharomyces cereuisiae were isolated and subjected to preliminary characterization. Complementation studies assigned these mutations to four complementation groups, one of which, cdc28, has been described previously. Genetic analysis revealed that these complementation groups define single nuclear genes, unlinked to one another. One of the three newly identified genes, cdc37, has been located in the yeast linkage map on chromosome IV, two meiotic map units distal to hom2.—Each mutation produces stage-specific arrest of cell division at start, the same point where mating pheromone interrupts division. After synchronization at start by incubation at the restrictive temperature, the mutants retain the capacity to enlarge and to conjugate.

Download Full-text

Centromere-Linkage Analysis and Consolidation of the Zebrafish Genetic Map

Genetics ◽

10.1093/genetics/142.4.1277 ◽

1996 ◽

Vol 142 (4) ◽

pp. 1277-1288

Author(s):

Stephen L Johnson ◽

Michael A Gates ◽

Michele Johnson ◽

William S Talbot ◽

Sally Horne ◽

...

Keyword(s):

Linkage Group ◽

Linkage Analysis ◽

Genetic Analysis ◽

Linkage Map ◽

Rapid Method ◽

Genetic Map ◽

Dna Polymorphisms ◽

Linkage Groups

Abstract The ease of isolating mutations in zebrafish will contribute to an understanding of a variety of processes common to all vertebrates. To facilitate genetic analysis of such mutations, we have identified DNA polymorphisms closely linked to each of the 25 centromeres of zebrafish, placed centromeres on the linkage map, increased the number of mapped PCR-based markers to 652, and consolidated the number of linkage groups to the number of chromosomes. This work makes possible centromere-linkage analysis, a novel, rapid method to assign mutations to a specific linkage group using half-tetrads.

Download Full-text