1. Chromosomal Mutations
Biology
Mrs. Harper
2/5/18

2. November 24, 2015
Have homework (Point Mutations WS) out

3. Do Now 2/5/18 Define mutation. What is a point mutation?
What is a deletion?
What is a substitution?
What is an insertion?

4. Do Now Continued (Reviewing Point Mutations)
Determine the type of mutation (substitution, insertion, or deletion)
Sequence: GATAGCTC
Mutated: GAAGCTC
Sequence: TGAACCT
Mutated: TGCACCT
Sequence: AAGCTCTT
Mutated: AAGCTCATT
Deletion
-T was removed
Substitution
-A was replaced with C
Insertion
-A was added

5. Chromosomal Mutations
Chromosomal mutations change the number of genes in a chromosome or the structure of a chromosome.
Unlike point mutations, chromosomal mutations affect the entire chromosome.

6. Types of Chromosomal Mutations
Four Types
1. Deficiency (Deletion)
2. Inversion
3. Translocation
4. Duplication

7. Deficiency (Deletion)
Deficiencies (Deletions) result when a piece of a chromosome breaks off or is lost during mitosis or meiosis.
This is a serious mutation and a zygote with this condition is unlikely to survive.

8. Inversion
Inversion is a mutation in which a segment of a chromosome detaches, changes direction and then recombines in the wrong order on the same chromosome.
All genes remain present, but they just appear in a different order.

9. Translocation
In translocation, a piece of one chromosome breaks off and attaches to a different chromosome.
Affects can be severe or not, depending on genes impacted and their distribution.

10. Duplication
Duplication occurs when an entire chromosome is copied more than once.
Results in formation of a daughter cell with extra chromosomes.

11. Video Recap

12. Nondisjunction
Nondisjunction is the failure of homologous chromosomes to separate properly during meiosis I, meiosis II or mitosis.
Results in daughter cells having abnormal chromosome numbers.

13. Examples of Nondisjunction
Down Syndrome (Trisomy 21)- extra chromosome on the 21st pair
2. Klinefelter Syndrome- adds an extra X chromosome to a male

14. Types of Mutations
Somatic mutations- occur in body cells, are NOT passed onto offspring
Example: Cancer
Germ mutations- occurs in sex cells (gametes), they CAN be passed onto offspring
Example: Colorblindness, Hemophilia

15. Positive Effects of Mutations
Provide genetic diversity, Could be neutral
Contribute to evolution and natural selection

16. Examples of Positive Mutations
Sickle cell resistance to malaria
People who are heterozygous for the sickle cell trait are resistant to malaria.

17. Negative Effects of Mutations
Life-threatening genetic disorders, Decreased life expectancy
More health complications, Abnormal physical traits

18. Examples of Negative Mutations
Severe Combined Immunodeficiency Disorder (SCID)
When individuals are born without an effective immune system. Severe because they are unable to fight off infection.

19. Assignment
Complete the Chromosome Worksheet and then read the articles/answer the questions over mutations.
You can also use your notes.
We are on CODE RED working independently.