Mutations Mutations Any mistake or change in DNA

Mutations Any mistake or change in DNA sequence What causes them? Random or Environmental

Chromosomal mutation: affects whole or part of a chromosome Gene mutation: Changes to the

1. Gene Mutations • Change in one or more nucleotides • Affects the amino

Point Mutation • Substitution: Change in a single base pair in DNA •

Some Point Mutations are Harmless • What amino acid is represented by the DNA

Some Point Mutations are Harmless • This type of point mutation is called a

Frameshift Mutation • Single base pair is added or deleted from DNA •

Kinds of Frameshift Mutations • Insertion: one or more bases are added into the

Nonsense Mutations • A point mutation that causes a premature STOP codon is called

Some mutations are beneficial • Gain-of-function mutations produce a functional protein that results in

Practice – Name that Mutation 1 2 3 4 5 6

Practice – Name that Mutation 1 2 Deletion ~ Frameshift Silent ~ Point 4

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Mutations

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

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 • Substitution: 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 • Causes a shift in the “reading frame” • Ex: Cystic Fibrosis EX: cystic fibrosis

Kinds of Frameshift Mutations • Insertion: one or more bases are added into the DNA strand • Deletion: one or more bases are removed from the DNA strand

Nonsense Mutations • A point mutation that causes a premature STOP codon 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

Practice – Name that Mutation 1 2 Deletion ~ Frameshift Silent ~ Point 4 3 Insertion, nonsense ~ Frameshift Point 6 5 Deletion ~ Frameshift Nonsense ~ Point

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