Mutations

Learning Targets:Describe different gene mutations.

Overview

• Cells occasionally make mistakes in copying their own DNA, by inserting the wrong base or skipping a base all together.

• Mutations - Changes in the genetic material

Kinds of Mutations

• Gene Mutations – Mutations that produce changes in a single gene.

• Chromosomal Mutations – Produce changes in whole chromosomes.

Gene Mutations

• Point Mutation– Gene mutations involving changes in one or a few

nucleotides.– Include substitutions (one base changed to another)– Include insertions and deletions (base inserted or

removed from the DNA sequence)

• Frameshift Mutation– Gene mutations that shift the “reading frame” of a

genetic message.

Chromosomal Mutations

• Changes in the number or structure of chromosomes.– May change the locations of genes on chromosomes or the

number of copies of some genes

• Four types:– Deletion – Involves the loss of all or part of a chromosome.– Duplication – Produces extra copies of chromosome parts.– Inversion – reverse the direction of parts of a chromosomes.– Translocation – part of a chromosome breaks off and

attaches to another.

Genetic Disorders

– Hemophilia, – Sickle cell anemia, – Down’s syndrome, – Turner’s Syndrome,– Williams Syndrome,– Tay-Sachs disease, – Cystic fibrosis, – Color blindness and – Phenylketomuria (PKU).

References

Miller, K. a. (2006). Biology. Boston: Pearson Education, Inc.