Mutations

What causes mutations?

Mistakes introduced into DNA

What are the impacts of mutations?

• May impact phenotype

• Harmful mutations may lead to genetic disorders

  • Decreases chances of survival

  • May cause inability to reproduce

What is gene mutation?

Change in the sequence of nucleotides of a gene

What is sickle cell anemia?

• Disease that gives rise to sickle-shaped red blood cells (RBCs)

• RBCs are far less efficient at binding and transporting oxygen around the body

• RBCs may clump and block blood flow through blood vessels

What is chromosomal mutation?

Number of chromosomes in a cell is different from normal

What causes chromosomal mutation?

Aneuploidy

• When a cell has an extra chromosome

• Results in a zygote with an extra chromosome

Non-disjunction

• Failure of 2 homologous chromosomes to separate to opposite poles at anaphase I

• Failure of sister chromatids to separate at anaphase II

What is Down syndrome?

• Additional chromosome 21

• Chances increase with an older mother

What are chromosomal mutagens?

Substances or agents that cause mutations

What are physical chromosomal mutations?

• Electromagnetic radiation e.g. gamma rays, X-rays and ultraviolet rays

What are chemical chromosomal mutations?

• Drugs

• Food preservatives

• Pesticides

• Tobacco