1. Mutations Notes

2. Mutations
A change in the DNA of the hereditary material of life

3. Mutations Can be: Good Bad Neutral Leads to adaptation Leads to cancer
Typically go unnoticed

4. Who’s affected?
If a mutation is in a somatic, or body cell, it will only change that person.
Also, skin cancer

5. Who’s affected?
If the mutation is in a gamete, or sex cell, the offspring will have that change also.
Also, family cancer lines
Albinism – mutation within the recessive genes that is passed down

6. Types of Mutations: Chromosomal: Deletions “ - ” Additions “ + ”
Inversions “flip flop”
Translocations “swap”
Nondisjunction “don’t split”

7. Chromosomal: Deletion Mutations
When a chromosome breaks and some of the genetic material is lost

8. Williams Syndrome
Williams syndrome is caused by a genetic abnormality, specifically a deletion of about 27 genes from the long arm of one of the two chromosome 7s.Typically this occurs as a random event during the formation of the egg or sperm from which a person develops. In a small number of cases it is inherited from an affected parent in an autosomal dominant manner.

9. Chromosomal: Insertion Mutations
When a fragment of a chromosome is inserted into another chromosome

10. Huntington's disease and the fragile X syndrome are examples of insertion mutation wherein trinucleotide repeats are inserted into the DNA sequence leading to these diseases.

11. Chromosomal: Inversion
When a broken chromosome segment is reversed and inserted back into the chromosome

12. Hemophilia A

13. Chromosomal: Translocations
When a fragment of one chromosome joins to a non-homologous chromosome

14. Disease Caused by Translocation
Cancer: Several forms of cancer are caused by acquired translocations (as opposed to those present from conception); this has been described mainly in leukemia
Down syndrome is caused in a minority (5% or less) of cases by a Robertsonian translocation of the chromosome 21 long arm onto the long arm of chromosome 14.
XX male syndrome: caused by a translocation of the SRY gene from the Y to the X chromosome
Infertility: One of the would-be parents carries a balanced translocation, where the parent is asymptomatic but conceived fetuses are not viable.

15. Chromosomal: Nondisjunction
Failure of chromosome pairs to separate properly during meiosis - (in anaphase-1 or 2)
It can result in a trisomy or monosomy

16. Nondisjunction disorders