2 Mutations Mutation: Any change in the DNA sequence Can be harmful, helpful, or neither.2 types: Gene mutations and chromosomal mutationsPoint mutation: occurs in a single point in the DNA sequenceGenerally occur during replicationThree types: substitution, insertion, and deletion.
3 Point mutations http://www. life. illinois SubstitutionOne single base is switchedUsually affects only one amino acidSickle cell disease in humansInsertion and deletionOne base is either inserted or removedDramatic changes affecting many amino acidsAlso called framshift mutationsMay have major effects on protiens
4 Chromosomal Mutation: Changes in chromosome number or structure1) INVERSION:the order of genes on a chromosome is inverted (reversed)2) TRANSLOCATION:the movement of a chromosome fragment to a nonhomologus chromosome
5 3. DELETIONLoss of a all or part of a chromosome4. DUPLICATIONDuplication of all or part of a chromosome
7 Causes of mutations Errors in replication 1 in 10 million bases is copied incorrectlyThis accumulates over timeMutagens (chemical or physical agents in the environment that cause mutations)Pesticides, tobacco smoke, environmental pollutantsEM radiation, X-rays, UV light
8 Effects of mutations Cells can sometimes repair damages from mutagens If not, several possible outcomes:Base-pairing can be disruptedDNA strands weaken, which can increase the chances of chromosomal mutations.
9 Helpful or harmful? Some mutations have no effect on the organism. Some are harmfulSome are helpfulHUGE variation!
10 Harmful mutationsMutations that dramatically alter the protein structure and gene activity are harmful.CancerSickle-cell disorderOther disorders (more on that later)
11 Beneficial Mutations?May alter an organism to make it more fit for its environmentInsects resisting pesticidesBacteria mutating to resist antibioticsHuman mutationsIncreased bone strengthViral resistance, such as HIVPolyploidyLarger fruits and veggies