Mutations

Mutations - changes in DNA causes a different protein to be made Usually is caught and fixed

Types of mutations Substitution Frameshift Duplication Missense Nonsense Frameshift Deletion Insertion Duplication

Substitution Mutations Point mutation – the change only happens to one amino acid Missense One base is replaced with another Nonsense That base replacement changes the amino acid to a stop codon, causing transcription to end early Achondroplasia (dwarfism)

Muscular dystrophy

Frameshift Mutation Changes every amino acid after the point of mutation Deletion One base is removed Insertion One base is added

Cystic fibrosis (deletion) Crohn’s disease (insertion)

Duplication Mutation One or more codons are repeated

Mutations Most occur in body cells – not passed to offspring Only mutations in reproductive cells show in offspring Mutations in fetal cells cause developmental problems Examples: thalidomide, FAS, polydactyly

Beneficial mutations Some have positive effect – allow organism to withstand environmental factors or reproduce quicker Example: color that allows animals to camouflage better

Mutations Mutagen- the thing that causes the mutation Ultraviolet X-ray radiation Alcohol Drug Nicotine Toxic Waste Random mutations causes not yet understood

Chromosomal Mutation Changes in whole chromosomes Can change number or structure of chromosomes may change gene location or number of genes