Mutation by Rimsha Khan.ppt

Mutations are changes in the nucleotide sequence of DNA that can ultimately change phenotypes. Mutations can occur in somatic cells or gametes and be passed to offspring. Most mutations are neutral or repaired by enzymes, but some can be harmful, like those that cause cancers, or beneficial by improving survival. There are two main types of mutations: chromosomal mutations, which involve changes in chromosome structure like deletions or duplications; and point mutations, where a single nucleotide is changed, as in sickle cell disease. Point mutations can be missense, nonsense, or frameshift, all of which can result in defective proteins if they occur in genes.