Mutations: a mistake made in DNA Gene Mutations Mutations: a mistake made in DNA

Gene Mutation Mutation that changes one gene

The Rat Hid And The Cat Sat And Got Fat Substitute a letter in the sentence makes it meaningless The Pat Hid And The Cat Sat And Got Fat Adding or deleting a letter is worse because ALL words change The Rat Hix Dan Dth Eca Tsa Tan Dgo Tfa T The Rah Ida Ndt Hec Ats Atat Ndg Otf At

Consequences of mutations Amino acids make polypeptides which makes proteins If one or more amino acids are wrong, then the organism can’t build the correct proteins

Gene Mutations: 2 types 1. Point mutations: mutation that occur at one point in the sequence 2. Frameshift mutations: mutation that shifts how all the codons are read

A G U C G G U G U A A G A G U C G G U U G U A A G insertion Frameshift Mutation

A G U C G G U G U A A G A G U C G G G U A A G Deletion Frameshift Mutation

A G U C G G U G U A A G A G U C G G U U U A A G Substitution Point Mutation

Chromosome Mutations Structure or number of chromosomes change

Duplication Broken part can reattach to a sister chromatid Normal chromosome ABCDE FGH Duplication of C and D ABCDCDE FGH

Deletion Normal chromosome ABCDE FGH Deletion of C and D ABE FGH

Inversion Broken part reattaches backwards Normal chromosome ABCDE FGH Inversion of B and C ACBDE FGH

Translocation Broken part attaches to ANOTHER chromosome Normal chromosome ABCDE FGH CDM NOPQR

When do mutations occur? Mitosis Meiosis

Mitosis Occurs only in the individual and does NOT get passed on to offspring Example: cancer Common reasons for mutations: UV radiation from the sun, tanning booths, x-rays, tobacco, asbestos, benzene, chemical pesticides

Meiosis Mutations that are passed on to offspring Examples: Sickle cell disease: substitution Tay-Sachs: frameshift Down syndrome: chromosome mutation on number 21