12-4 mutations objective: contrast gene mutations & chromosomal mutations are all mutations bad?

12-4 Mutations

Objective:Contrast gene mutations & chromosomal mutations

Are all mutations

bad?

What is a mutation?

• Changes in genetic information.• Usually occurs in DNA replication.

Kinds of Mutations

• Gene Mutations: only changes 1 gene– Point Mutations occur when 1 or a few

nucleotides change.– Ex:

DNA: G A T C T C A G G C T A

mRNA: C U A G A G U C C G A U

Protien: Leu-Glu-Ser-Asp

Original

DNA: G A T C T A A G G C T A

mRNA: C U A G A U U C C G A U

Protien: Leu-Asp-Ser-Asp

Mutation

Oops!

Kinds of Mutations

• Chromosomal Mutations: change entire DNA– Frameshift mutations occur when the entire

reading frame changes.– Ex: A nucleotide gets added (insertion).

DNA: G A T C T C A G G C T A

mRNA: C U A G A G U C C G A U

Protien: Leu-Glu-Ser-Asp

Original

DNA: G A T C T A C A G G C T A

mRNA: C U A G A U G U C C G A U

Protien: Leu-Asp-Val-Arg

MutationA

Kinds of Mutations

• Chromosomal Mutations: change entire DNA– Frameshift mutations occur when the entire

reading frame changes.– Ex: A nucleotide gets added (insertion).– Ex: A nucleotide gets taken away (deletion).

DNA: G A T C T A G G C T A

mRNA: C U A G A G U C C G A U

Protien: Leu-Glu-Ser-Asp

Original

DNA: G A T C T A G G C T A A

mRNA: C U A G A U C C G A U U

Protien: Leu-Glu-Ser-Iso

Mutation

C

Kinds of Mutations

• Chromosomal Mutations: change entire DNA– Change in number of chromosomes.– Ex: Down Syndrome (47 chromosomes)