DNA damage and Mutagenesis 0.0 / 5 ? BiologyGeneticsUniversityNone Created by: ablou98Created on: 12-11-19 11:41 DNA damage and Mutagenesis -DNA adducts -cross links -strand breaks -covalent modifications -DNA intercalation 1 of 15 mutations -point mutations -insertion/deletion (indels) -structural (clastgenic) -numerical(aneuploidy) 2 of 15 the central dogma 3 of 15 dna damaging agents - genotoxins/genotoxicants --> CARCINOGENS - mutagens = gene mutations clastogens = double strand break aneugens = chromosomal change 4 of 15 exogenous toxins environment = cigarette smoke 5 of 15 genotoxic patterns direct indirect characteristic patterns of DNA damage = preferred sites to react with DNA = mutagen 6 of 15 endogenous toxins Reactive oxygen species (ROS) and SAM - produced in the bosy by metabolism - unavoidable - spontaneous base alterations 7 of 15 gene mutations - substitutions point mutations - transitions - transversions three different ways to affect amino acids silent missense nonsense 8 of 15 base substitutions effect on protein function gain of function - incewased expression of gene = increased activity e.g proto- oncogene --> oncogene loss of function - inactivating mutations = destroy protein function, nonsense mutations e.g. tumour supressor genes dominant negative - mutated allele inhibits the function of the wildtype allele 9 of 15 point mutations and disease effect depends on which cell they occur genotoxic exposure, errors in replication, carrier.sufferer (infertility) --> birth and development defects, hereditary disease, childhood cancers well defined relationship with cancers 10 of 15 mechanisms of malsegregation 11 of 15 DNA douuble strand breaks caused by: ionizing radiation and other clastogens, stalled and collapsed replication forks repaired by HR, NHEJ associated with: miscarriages, developmental defects, cancer 12 of 15 types of aberrations gene loss gene amplification transcription dysregulation transcriptional dysregulation fusion protein gene loss transcriptional dysregulation fusion protein 13 of 15 ring chromosomes can form from any chromosome two types: non-supernumerary --> loss of genes, partial monosomy supernumerary --> gain of genes, partial trisomy 14 of 15 marker chromosome (MAR) structually abnormal chromosomes smaller than a chromosome lacjing distinct bands partial trisomy there could be some extra active genetic info present 15 of 15
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