Part 2 book “Essentials of genretics” has contents: Regulation of gene expression, the genetics of cancer, genomics, bioinformatics, and proteomics, applications and ethics of genetic engineering and biotechnology, developmental genetics, quantitative genetics and multifactorial traits, population and evolutionary genetics, and other contents. | 14 Gene Mutation, DNA Repair, and Transposition CHAPTER CONCEPTS ■■ Mutations comprise any change in the base-pair sequence of DNA. ■■ Mutations are a source of genetic variation and provide the raw material for natural selection. They are also the source of genetic damage that contributes to cell death, genetic diseases, and cancer. ■■ Mutations have a wide range of effects on organisms depending on the type of base-pair alteration, the location of the mutation within the chromosome, and the function of the affected gene product. ■■ Mutations can occur spontaneously as a result of natural biological and chemical processes, or they can be induced by external factors, such as chemicals or radiation. ■■ Single-gene mutations cause a wide variety of human diseases. ■■ Organisms rely on a number of DNA repair mechanisms to detect and correct mutations. These mechanisms range from proofreading and correction of replication errors to base excision and homologous recombination repair. ■■ Mutations in genes whose products control DNA repair lead to genome hypermutability, human DNA repair diseases, and cancers. ■■ Transposable elements may move into and out of chromosomes, causing chromosome breaks and inducing mutations both within coding regions and in gene-regulatory regions. Pigment mutations within an ear of corn, caused by transposition of the Ds element. T he ability of DNA molecules to store, replicate, transmit, and decode information is the basis of genetic function. But equally important are the changes that occur to DNA sequences. Without the variation that arises from changes in DNA sequences, there would be no phenotypic variability, no adaptation to environmental changes, and no evolution. Gene mutations are the source of new alleles and are the origin of genetic variation within populations. On the downside, they are also the source of genetic changes that can lead to cell death, genetic diseases, and cancer. Mutations also provide the .
