Gene and Chromosomal Mutations Genetic Changes Gene and Chromosomal Mutations

I. Intro. to Mutations A. Mutations are a result in a change in DNA sequence: 1. A protein with a different AA sequence could be produced. 2. Germ Cell - If mutations occur in sex cells they may be passed on to the next generation. 3. Somatic- A mutation occurring only in body cells may be a problem for the individual but will not be passed on to the offspring.

I. Cont. Intro. to Mutations B. Mutations may be classified as chromosomal alterations or gene mutations 1. Chromosomal alterations are generally more severe because many genes are usually involved.

II. Types of Gene Mutations A.Silent mutation-any mutation that is not expressed because it does not cause a change in amino acid chain. B. Point mutation (base-pair substitution)- 1 base is replaced by a different base

-Point mutation -Only one nucleotide changes, but it makes a different protein

1. Insertion- one or more bases are added C. Frameshift- causes every codon in the DNA sequence to be changed after the mutation: 1. Insertion- one or more bases are added 2. Deletion- one or more bases are removed A

III. Chromosomal Alterations 1. Deletion - part of chromosome is left out. 2. Duplication - part of chromatid breaks off add attaches to the sister chromatid creating a duplication of genes on the same chromosome. **Deletion and duplication mutations are errors that occur during crossing over in Meiosis I. 3. Translocation - when part of one chromosome breaks off and is added to a different chromosome. 4. Inversion - when part of a chromosome breaks off and is reinserted backwards.

-Chromosomal Deletion A dinky Y chromosome and the hairy ear gene on the Y chromosome