* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Mutations Terminology
Vectors in gene therapy wikipedia , lookup
Transfer RNA wikipedia , lookup
Gene expression profiling wikipedia , lookup
Koinophilia wikipedia , lookup
Cancer epigenetics wikipedia , lookup
BRCA mutation wikipedia , lookup
Therapeutic gene modulation wikipedia , lookup
Skewed X-inactivation wikipedia , lookup
Neuronal ceroid lipofuscinosis wikipedia , lookup
No-SCAR (Scarless Cas9 Assisted Recombineering) Genome Editing wikipedia , lookup
Gene expression programming wikipedia , lookup
Genome (book) wikipedia , lookup
Genome evolution wikipedia , lookup
Cell-free fetal DNA wikipedia , lookup
Genetic drift wikipedia , lookup
Designer baby wikipedia , lookup
X-inactivation wikipedia , lookup
Nucleic acid analogue wikipedia , lookup
Gene therapy of the human retina wikipedia , lookup
Site-specific recombinase technology wikipedia , lookup
Saethre–Chotzen syndrome wikipedia , lookup
Oncogenomics wikipedia , lookup
Artificial gene synthesis wikipedia , lookup
Expanded genetic code wikipedia , lookup
Population genetics wikipedia , lookup
Genetic code wikipedia , lookup
Dominance (genetics) wikipedia , lookup
Microevolution wikipedia , lookup
MUTATION AND MUTAGENS DEFINITIONS mutation; a heritable change in the DNA At the level of the phenotype/genotype: recessive mutation produces recessive allele: A a dominant mutation produces dominant allele: b B forward: from the common to a new allele reverse: a return to the original allele somatic: a mutation in a somatic cell suppressor: a second mutation "corrects" another intragenic -2nd amino acid change restores folding/activity intergenic - change at second gene locus masks error ex. nonsense suppressor; tRNA anticodon change permits recognition of stop codon (in competition with Release Factors) At the DNA level: point; a single base change; can be reverted transition; (AT GC changes; purine for purine) transversion; (puríne for pyrimidine); (AT TA or AT CG or GC CG) single base addition or deletion At the level of mRNA translation missense: wrong amino acid inserted (neutral if no effect on the enzyme made, but missense mutations are often "leaky", temperature sensitive or low enzymatic activity, etc) nonsense: the mutation creates a stop codon samesense: (or silent) -the same amino acid will be coded frameshift: added or lost base changes reading frame Detection of Mutation; Measuring Mutation Rates: First test was devised by H. J. Muller for use in Drosophila and proved that X-rays are mutagenic. Relied on three X-linked "genes" C = dominant crossover suppressor (actually an inversion) l = recessive lethal B = Bar eyes BB females have rod-shaped eyes, Bb are wide-bar and bb are normal kidney shaped eyes Protocol: wide bar females heterozygous for the 3 genes were crossed to normal but x-irradiated males. The wide bar female progeny, ClB irr. containing one X chromosome and one X were crossed to normal males. Any female that produced daughters but no sons irr had a new recessive lethal on the X . The dose response was linear until high doses masked individual mutations. The rate was 3 lethals/100 irradiated chromosomes per 1 Kr. More current tests include the "Ames test" that detects reversion of a known mutation in a gene in Salmonella to measure both the rate and type of base change induced by a test substance. A series of mutant strains, all defective in a gene required to make the amino acid histidine can differentiate specific transition-, transversionand frameshift-inducing agents, because only revertant cells can grow into a colony on minimal medium. See: AMES test image Strains can be obtained from the Salmonella Genetic Stock Center: http://www.acs.ucalgary.ca/~kesander/ Another direct test using mammalian cells is also widely used. It is based on mouse cancer cells that will not grow on medium containing trifluorothymidine unless a mutation eliminates the second (functional) copy of the Thymidine kinase gene. This test is not limited to point mutations. See: http://www.mlamutations.com/mla/mla.html