منابع مشابه
Adaptive Amplification An Inducible Chromosomal Instability Mechanism
Adaptive mutation is an induced response to environmental stress in which mutation rates rise, producing permanent genetic changes that can adapt cells to stress. This contrasts with neo-Darwinian views of genetic change rates blind to environmental conditions. DNA amplification is a flexible, reversible genomic change that has long been postulated to be adaptive. We report the discovery of ada...
متن کاملCFAR adaptive threshold for ESM receiver with logarithmic amplification
An adaptive threshold with constant false alarm rate (CFAR) property is proposed to be used in a channelized electronic support measures (ESM) system with logarithmic video ampli'cation. For this purpose, two CFAR processors are designed which are in fact modi'ed excision (MEx) and adaptive MEx (AMEx) processors, previously presented by authors, but modi'ed for the logarithmic ampli'cation case...
متن کاملMultiple pathways of selected gene amplification during adaptive mutation.
In a phenomenon referred to as "adaptive mutation," a population of bacterial cells with a mutation in the lac operon (lac-) accumulates Lac+ revertants during prolonged exposure to selective growth conditions (lactose). Evidence was provided that selective conditions do not increase the mutation rate but instead favor the growth of rare cells with a duplication of the leaky lac allele. A furth...
متن کاملRapid adaptive amplification of preexisting variation in an RNA virus.
The amount and nature of preexisting variation in a population of RNA viruses is an important determinant of the virus's ability to adapt rapidly to a changed environment. However, direct quantification of this preexisting variation may be cumbersome, because potentially beneficial alleles are typically rare, and isolation of a large number of subclones is required. Here, we propose a simpler m...
متن کاملThe amplification model for adaptive mutation: simulations and analysis.
It has been proposed that the lac revertants arising under selective conditions in the Cairns experiment do not arise by stress-induced mutagenesis of stationary phase cells as has been previously assumed. Instead, these revertants may arise within growing clones initiated by cells with a preexisting duplication of the weakly functional lac allele used in this experiment. It is proposed that sp...
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ژورنال
عنوان ژورنال: Cell
سال: 2000
ISSN: 0092-8674
DOI: 10.1016/s0092-8674(00)00176-8