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MutationsChapter 12-4

+What are mutations?Any change to the genetic code

Gene mutations: A change in one or a few nucleotides in a gene

Chromosomal Mutations: a change in the number or structure of chromosomes

+What are mutations?Gene mutations

1) point mutation (substitution): Change of 1 base into another resulting in a change in 1 amino acid in the sequence

+ Effects of substitutions

Some substitutions result in coding for same amino acid

Some change amino acid but doesn’t affect overall protein

Some change 1 amino acid and changes structure of entire protein

+ Sickle Cell Anemia

Normal hemoglobin

Sickle CellHemoglobin

+2) Frameshift: Shift in the reading frame that causes every amino acid after the mutation to be different.

(Caused by Insertion or deletion)

Insertion

Deletion

+ Effects of Frameshift mutationsGood:

disables CCR5 HIV receptor which allows HIV virus to attack Immune cells

Mutations that allow evolution of species (survival of the fittest)

Bad: Causes severe disorders:Tay SachsChron’s diseasColor Blindness

+What are mutations?Chromosomal mutations:

A change in one or a few chromosomes4 Types: 1) Deletion: Loss of part / all2) Duplication: Segment is repeated3) Inversion: Segment is reversed4) Translocation: Segment breaks off and is reattached

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+ Effects

Down Syndrome Turners Syndrome