Genetic Instability in Ascobolus Immersus: Modalities of Back-mutations, Intragenic Mapping of Unstable Sites, and Unstable Insertion. Preliminary Biochemical Data
- B. Decaris,
- F. Francou,
- A. Kouassi,
- C. Lefort, and
- G. Rizet
This extract was created in the absence of an abstract.
Excerpt
Genetic instability in Ascobolus immersus has been the subject of several previous reports; the main results of these studies are summarized below.
The unstable mutants that have been studied are affected in the color or the size of ascospores. They revert to wild type with very high frequencies of revertant asci: from 0.001 to 0.70. Most often, however, these frequencies range from 0.01 to 0.10. The reversions are indistinguishable from back-mutations. So, in unstable mutant X unstable mutant crosses, the existence of two reverted meiotic products among the four indicates that reversion occurred before meiosis. The same crosses also produce a few stable mutant strains.
Among the several wild stocks of A. immersus, such unstable mutants, all of spontaneous origin, have only been found in stock 50 (Rizet et al., 1979). The first unstable mutant was obtained in a cross between two wild-type strains isolated from nature. The others were...
