chromosomal mutation


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Related to chromosomal mutation: gene mutation

chromosomal mutation

changes to the chromosome complement or structure of cells or organisms. There are two major types:
  1. numerical, affecting whole chromosomes (see POLYPLOID and ANEUPLOIDY), and
  2. structural, affecting genetic arrangement within chromosomes. These are usually of a fairly major type (compare POINT MUTATION) and often cause severely adverse effects. Such structural mutations are classified into various types:
  1. inversion, the rearrangement of a chromosomal segment so that it has the reverse sequence, e.g. ABCDE ----> ADCBE;
  2. deletions, the removal of a segment;
  3. duplication, the repeating of a segment either next door to the original or elsewhere along the chromosome;
  4. translocation, the exchange of segments between nonhomologous chromosomes.
References in periodicals archive ?
The dominant mechanisms of fluoroquinolone resistance identified are 1) chromosomal mutations causing reduced affinity of DNA gyrase and topoisomerase IV for fluoroquinolones and 2) overexpression of endogenous MDR pumps.
gonorrhoeae were resistant to penicillin G (MIC [is greater than or equal to] 2 mg/L) and tetracycline (MIC 2 [is greater than or equal to] mg/L and [is less than] 16 mg/L), respectively, by chromosomal mutation. In contrast, the percentage of strains with plasmid-mediated resistance to penicillins and tetracycline has remained stable at approximately 15% since 1994.
The extensive use of colistin in veterinary medicine to treat gastrointestinal infections caused by Enterobacteriaceae has contributed to chromosomal mutations mediated by the plasmid mcr-1 to codify resistance to colistin in Gram-negative bacilli.
Resistance phenotypes have been more thoroughly investigated in Escherichia coli and linked to chromosomal mutations in the target (murA) or transporter (glpT and uhpT) genes or less frequently to plasmid-mediated fosfomycin resistance genes (fosA, fosB, fosC) encoding glutathione S-transferases that inactivate the drug (4).
"Because different forms of cancer are associated with different chromosomal mutations, we believe analysis of exosome DNA taken from blood samples may not only help determine the presence of a cancerous tumor somewhere in the body, but identify mutations without a need for tumor sample.
In addition to the acquired resistances caused by chromosomal mutations, M.
Kalluri added that because different forms of cancer are associated with different chromosomal mutations, they believe analysis of exosome DNA taken from blood samples may not only help determine the presence of a cancerous tumour somewhere in the body but also identify mutations without a need for tumour sample.
The PrenaTest is being further developed "to identify other chromosomal mutations such as Trisomy 13 and 18," said Dr.
During vertical evolution, microbes develop advantageous chromosomal mutations that they pass on to their progeny.
pallidum chromosomal mutations associated with azithromycin resistance and treatment failures have been documented in several areas in the United States."
However, there is less direct evidence that illustrates chromosomal mutations of asbestos fibers in various organs and tissues in intact organisms.