2Mutations Severe Combined Immunodeficiency Disorder (SCID) EctrodactylySickle Cell AnemiaHeterochromia iridiumProgeriaHypertrichosis
3What is a mutation? @A mutation is any change in a cell’s DNA@ A mutation can occur in an individual gene- results in a single changed protein- bacterial resistance to antibiotics is an example of a beneficial gene mutation
4What is a mutation continued A mutation can occur in a chromosome- a chromosome contains many genes- chromosomal mutations affect manyproteinsExamples: Down SyndromeEdward’s SyndromeCri-du-Chat
5What Causes Mutations?Can be caused by mutagens- a physical or chemical cause of mutation. Examples: UV light, radiation, drugs, and benzene.Mutagens are often also carcinogens – anything that causes cancerCan be natural, random events.- mutations occur in 1/100,000 DNA replicationsMutations do not have to be bad (evolution)
6Gene Mutations 1. Point Mutations 2. Frameshift Mutations
7Point Mutations Substitution @A single nucleotide is Can change one amino acid in a proteinMilk – MileGGACAATCA GGACCATCAproline -valine-serine proline-glycine-serine
8Frameshift Mutations@A nucleotide is either inserted or deleted from a-all of the triplets from the point of mutation onward will be changed
9Frameshift Mutations Insertion An insertion occurs when a nucleotide is added to a geneExample: A nucleotide is insertedThe fat cat ate the ratThe faa tca tat eth era t-the extra nucleotide shifts all of the triplets that follow
10Frameshift Mutations Deletions A deletion occurs when a nucleotide is removed from a gene.Example: A nucleotide is removedThe fat cat ate the ratThf atc ata tet her at
13Chromosomal Mutations Chromosomal mutations involve changes in the number or structure of chromosomes.
14Chromosomal Mutations Deletion involves the loss of all or part of a chromosome.
15Chromosomal Mutations Duplication produces an extra copy of all or part of a chromosome.
16Chromosomal Mutations Inversion reverses the direction of parts of a chromosome.
17Chromosomal Mutations Translocation occurs when part of one chromosome breaks off and attaches to another.
18Harmful and Helpful Mutations The effects of mutations on genes vary widely. Some have little or no effect; and some produce beneficial variations. Some negatively disrupt gene function.@However, without mutations, organisms cannotMutations are the source of genetic variability in a species.
19Harmful EffectsSome of the most harmful mutations are those that dramatically change protein structure or gene activity causing genetic disorders.Some cancers, for example, are the product of mutations that cause the uncontrolled growth of cells.
20Harmful EffectsSickle cell disease is a disorder associated with changes in the shape of red blood cells. Normal red blood cells are round. Sickle cells appear long and pointed.@Sickle cell disease is caused by a point mutation in one of the polypeptides found in (the blood’s principal oxygen-carrying protein)
21Beneficial EffectsMutations often produce proteins with new or altered functions that can be useful to organisms in different or changing environments.For example, mutations have helped many insects resist chemical pesticides.
22Beneficial EffectsPlant and animal breeders often make use of “good” mutations.The condition in which an organism has extra sets of chromosomes is called polyploidy.