Mutations Chapter 12-4

Any change to the genetic code Gene mutations: What are mutations? Any change to the genetic code Gene mutations: A change in one or a few nucleotides in a gene Chromosomal Mutations: a change in the number or structure of chromosomes

What are mutations? Gene mutations 1) point mutation (substitution): Change of 1 base into another resulting in a change in 1 amino acid in the sequence

Effects of substitutions Some substitutions result in coding for same amino acid Some change amino acid but doesn’t affect overall protein Some change 1 amino acid and changes structure of entire protein

Sickle Cell Anemia Normal hemoglobin Sickle Cell Hemoglobin

2) Frameshift: Shift in the reading frame that causes every amino acid after the mutation to be different. (Caused by Insertion or deletion) Deletion Insertion

Effects of Frameshift mutations Good: disables CCR5 HIV receptor which allows HIV virus to attack Immune cells Mutations that allow evolution of species (survival of the fittest) Bad: Causes severe disorders: Tay Sachs Chron’s diseas Color Blindness

Chromosomal mutations: What are mutations? Chromosomal mutations: A change in one or a few chromosomes 4 Types: 1) Deletion: Loss of part / all 2) Duplication: Segment is repeated 3) Inversion: Segment is reversed 4) Translocation: Segment breaks off and is reattached

Effects Down Syndrome Turners Syndrome