Mutations

Mutations Any change in the DNA structure (specifically the order of nitrogen bases) is a mutation. Mutations can be helpful, harmful, or neutral. Helpful – can create diversity in a population Harmful – can cause things like cancer Neutral – can have absolutely no effect at all A mutagen is something that causes mutations in the DNA (for example: smoking, radiation from the sun etc)

Two Basic Mutation Categories: 1. Gene mutations 2. Chromosomal mutations Produce changes in a single gene Gene that produces the enzyme lactase doesn’t work correctly, and the person cannot digest lactose Produce changes in a whole chromosome Person inherits an entire extra chromosome, or is missing an entire chromosome Person’s chromosome gets rearranged

Gene Mutations: Point Mutations 1. Substitution 2. Insertion or 3.Deletion One base is changed to a different base Usually only affects 1 amino acid, or has no effect CCC changed to CCA Still proline CCC changed to ACC Now threonine instead Makes a totally different protein One base is inserted or deleted from a sequence Effects can be dramatic *AKA: Frameshift mutations because they shift the sequence left or right Can shift every amino acid that follows the mutation, causing BIG PROBLEMO!

Point Mutation Examples: If our DNA was AATTGGCC An insertion would be AATTAGGCC A deletion would be AATGGCC A substitution would be AAATGGCC

Guess the Mutation… Substitution Deletion Insertion Changing the DNA sequence changes the amino acid sequence, which changes the protein that is made, which CAN change the organism

Chromosomal Mutations: Change # or structure of chromosomes: Deletion – segment gets deleted Duplication – segment gets duplicated Inversion – 2 segments get switched Translocation – part of one chromosome breaks off and attaches to another Deletion Duplication Inversion Translocation

Chromosomal Mutations Types of Mutations Chromosomal Mutations Gene Mutations

Chromosomal Mutations Types of Mutations Chromosomal Mutations Gene Mutations