1. Changes to the Genetic Code
pp and 231

2. Alterations to the Code
A change in one or many genetic traits
Can be either 1) chromosomal or 2) a gene mutation
Can happen in gametes or body cells
If the change occurs in the gametes the trait can be inherited by the offspring
Can be lethal (deadly) even before birth
Typically, changes in the body cells could result in cancer

3. Chromosomal Alterations
More than 1 trait can be affected since whole segments of DNA can be altered
Cri du chat, which is caused by the deletion of part of the short arm of chromosome 5
"Cri du chat" means "cry of the cat" in French, and the condition was so-named because affected babies make high-pitched cries that sound like those of a cat. Affected individuals have wide-set eyes, a small head and jaw, and are moderately to severely mentally retarded and very short.
Wolf-Hirschhorn syndrome, which is caused by partial deletion of the short arm of chromosome 4. It is characterized by severe growth retardation and severe to profound mental retardation.

4. Deletion loss of a piece of chromosome
Cri du chat, which is caused by the deletion of part of the short arm of chromosome 5
"Cri du chat" means "cry of the cat" in French, and the condition was so-named because affected babies make high-pitched cries that sound like those of a cat. Affected individuals have wide-set eyes, a small head and jaw, and are moderately to severely mentally retarded and very short.
Wolf-Hirschhorn syndrome, which is caused by partial deletion of the short arm of chromosome 4. It is characterized by severe growth retardation and severe to profound mental retardation.

6. Inversion Chromosome breaks off and reattaches in reverse
EX. Hemophilia

7. Translocation
Piece breaks off and attaches to another

8. Gene Mutations A change in the genetic code of one gene
Typically only one trait is affected

9. Types of Mutations Silent: a normal protein is still made
Missense: faulty protein produced
Nonsense: an incomplete protein is made due to an early stop

10. Causes of the Mutations
Results from a substitution, addition, or removal of a nucleotide
Also called a point mutation

12. Substitution
Makes a new codon that could result in the same amino acid (silent) mutation)
A new codon can also result in an early stop (nonsense)
If a different amino acid is made the structure of the protein can be altered if a different amino acid is made (missense)
EX. Sickle cell anemia

13. Frame shift mutation Due to the removal or addition of a nucleotide
Causes shift in entire reading frame and results in an entirely different protein (missense) or no protein due to an early stop (nonsense)