Gene Mutations Essential Question How do changes in

Gene Mutations Essential Question: How do changes in the DNA nucleotide sequence affect the resulting protein?

Mutations Any mistake or change in DNA sequence What causes them? Random or Environment influences – X-rays, UV rays, radioactive materials, chemicals, medications

More about mutations • Can be beneficial, harmless, or harmful • 2 types: Gene & Chromosomal

Chromosomal mutation: affects whole or part of a chromosome Gene mutation: Changes to the bases in the DNA of ONE gene

1. Gene Mutations • Change in one or more nucleotides • Affects the amino acids and protein produced • 2 types

Point Mutation • Change in a single base pair in DNA • Ex: The dog bit the CAT The dog bit the CAR

Sickle Cell Anemia

Some Point Mutations are Harmless • What amino acid is represented by the DNA sequence GGA? • What amino acid is represented by the DNA sequence GGC? • This change in the 3 rd base of the codon is a point mutation, yet the amino acid would remain the same. Therefore, the protein would NOT be affected.

Some Point Mutations are Harmless • This type of point mutation is called a silent mutation. • Silent Mutations are possible due to the redundancy in the genetic code.

Frameshift Mutation • Single base pair is added or deleted from DNA • Ex: Cystic Fibrosis

FRAME SHIFT MUTATION Causes a shift in the “reading frame” thefatcatatetherat the fat cat ate the rat __________ INSERTION thefatcataatetherat the fat cat aat eth era t DELETION thefatcatatetherat the fat ata tet her at

FRAME SHIFTS Frame shift mutations change every Amino acid ______ in the ______ protein that follows the shift. Frame shifts can alter a protein so function much it is unable to _______

Location of the shift is important! AT BEGINNING the fat cat ate the rat the fac ata tet her at AT END the fat cat ate the rat the fat cat ate thr at BEGINNING MUTATIONS AT _______OF GENE DAMAGE _____ OF THE CODE! MORE

Nonsense Mutations • A point mutation or a shift in the reading frame can sometimes cause a premature STOP codon • This type of mutation is called a nonsense mutation • If the nonsense mutation occurs early in the m. RNA sequence, the protein is greatly shortened and most likely non functional

Some mutations are beneficial • Gain-of-function mutations produce a functional protein that results in an entirely new trait • These mutations are usually beneficial and result in an advantage in an organism’s environment • EX: The mutation that resulted in eyesight

Practice – Name that Mutation 1 2 3 4 5 6