Term
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Definition
| unrepaired DNA damage, can still get repaired |
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Term
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Definition
| permanent change in sequence of a polynucleotide |
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Term
| mutation degree of damage |
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Definition
| related to function of altered gene, location of mutation in gene, whether somatic or germline |
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Term
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Definition
| alteration in 1 nucleotide due to base-pairing error, radiation, or chemical damage |
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Term
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Definition
| movement of gene from place to place on chromosome, may alter expression of that gene or nearby genes |
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Term
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Definition
| when large segments of chromosomes change location, extremely rare |
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Term
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Definition
| point mutation, one base pair is inserted, results in frameshift mutation |
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Term
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Definition
| point mutation, one base pair is deleted, results in frameshift mutation |
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Term
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Definition
| most common point mutation, replacement of single base pair, usually transition (purine->purine or pyrimidine->pyrimidine), very rare- transversion (purine->pyrimidine) |
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Term
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Definition
| mutation has no functional effect |
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Term
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Definition
| mutation changes sequence to code for different amino acid |
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Term
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Definition
| mutation codes for a stop codon |
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Term
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Definition
| a screening to calculates mutation frequency |
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Term
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Definition
| can lead to transition point mutation, ex. 5-bromo-dUTP incorporated into DNA opposite A, then through replication wrong base bonds |
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Term
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Definition
| can lead to transition point mutation, ex. nitrous acid (preservative in meat) converts C->U by oxidative deamination, ex. hydroxylamine reacts w/ C allowing base pairing with adenine |
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Term
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Definition
| lead to cross-linking, strand breaks, point mutations, deletions, and insertions by adding alkyl groups to DNA, ex. MNNG - transition mutation, nitrosamine - transition mutation |
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Term
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Definition
| slide between stacked bases in DNA, result in insertion/deletion and frameshift mutation |
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Term
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Definition
| can form pyrimidine dimers, alter bases, cleave phosphodiester bond, cross-link duplex strands |
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Term
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Definition
| direct repair, mismatch repair, base excision, or nucleotide excision - all extremely inefficient energetically, repair using the undamaged strand as a template, often redundant mechanisms exist to correct errors |
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Term
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Definition
| 1. repairs via methyltransferase, results in irreversible inactivation of MGMT, MGMT levels proportional to damage level cell can handle 2.DNA photolyase uses UV energy to cleave primidine dimer |
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Term
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Definition
| picks DNA that is unmethylated (signals newly synthesized strand) resynthesizes section between methyl groups, mech. missing in hereditary nonpolyposis colorectal cancer (HPCC) |
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Term
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Definition
| mediated by DNA glycosylases that recognizes, hydrolyzes the glycosidic bond, removes damaged base leaving an apyrimidinic site in DNA, AP endonucleaes nicks DNA backbone, pol I replaces base in 5'->3', DNA ligase seals the strand |
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Term
| nucleotide excision repair |
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Definition
| excinuclease hydrolyzes 2 phosphodiester bonds on either side of lesion, DNA helicase releases fragment of nucleotides (not just bases), DNA polymerase replaces bases, DNA ligase seals the gap; xeroderma pigmentosum (extreme sensitivity to UV) - disease results from defect in pyrimidine dimer repair |
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Term
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Definition
| rearrangement of genetic info within and among DNA molecules, sometimes a programmed part of development, ex. millions of possible immunoglobulins |
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Term
| homologous genetic recombination |
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Definition
| exchange between DNA molecules that share an extended region of nearly identical sequence, used for DNA repair process in prokaryotes - repair bacterial DNA via exchange of identical sequence, used for genetic diversity in meiosis of eukaryotes or physical link between homologous chromosomes for orderly segregation during cell division |
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Term
| site-specific recombination |
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Definition
| exchange of genetic info at specific DNA sequence, requires enzyme recombinase, 1. 1 strand in each DNA is cleaved at specific location, 2. cleaved strands join to form Holliday structure, critical to certain types of gene expression,, embryonic development, and in replication cycles of some viral and bacterial DNAs |
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Term
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Definition
| short segment of DNA that can 'jump' from one location in genome to another, does not require homology, tightly regulated, can change expression or result in cell death, ex. antibiotic resistance |
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Term
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Definition
| these proteins are involved in recombinational DNA repair, defects in either gene increase chance of developing breast cancer |
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