Section 11.3

Genetic Changes

Mutations Any change in the DNA sequence that also

changes the protein it codes for.

Mutations in reproductive cells: May produce a new trait May result in a protein that does not work

correctly Protein may be nonfunctional causing the

embryo to not survive

Mutations in body cells: Would not be passed

on to offspring

May impair the function of the cell

cancer

Point Mutation The change in a single

base pair in DNA

Can change a single amino acid in the chain resulting in a change in the entire protein produced.

Frameshift Mutation A mutation in which a

single base is added or deleted from DNA

Would cause nearly every amino acid in the protein after the addition or deletion to be changed.

Chromosomal Mutation When parts of chromosomes are broken

off or lost during mitosis or meiosis

Chromosomes break and rejoin incorrectly

Usually do not survive. If they do, they are usually sterile

Types of Chromosomal Mutations: 1. Deletion – when part of

a chromosome is left out

2. Insertions – when a part of a chromatid breaks off and attaches to its sister chromatid. The result is a duplication of genes on the same chromosome.

Types of Chromosomal Mutations 3. Inversions – when

part of a chromosome breaks off and is reinserted backwards.

4. Translocations – when part of one chromosome breaks off and is added to a different chromosome.