1. Do now activity
What is the difference between codominance and incomplete dominance?
What is the difference between a mono-hybrid punnet square and a di- hybrid punnet square?

2. Section 4-4: Genetic variation
Essential Question:
Why is there variation among organisms?
Learning Target
Use a variety of data to support the claim that genetic variation results from three sources.
Explain the source of variation among organisms.
Section 4-4: Genetic variation

3. announcements Biology Tutoring schedule W&F @ 7:00AM Section 4 Test
Scheduled for Friday: 11/17/17
Section 4 Lab
TBA
Class website will be updated today

4. announcements Available Extra Credit: 3 Tissue Boxes = 1 class pass
Color Printer Paper = 1 class pass Plastic Pencil Box = 1 class pass

5. Don’t forget to chunk your notes!

6. What is genetic variation?
overview
What is genetic variation?

7. Why do you think variation is important?
overview
Why do you think variation is important?

8. There are 3 sources of genetic variation.
overview
There are 3 sources of genetic variation.

9. Don’t forget to chunk your notes!

10. Source #1: Gene Shuffling
Meiosis followed by sexual reproduction
Most genetic variations are due to gene shuffling
In humans this produces 8.4 million different combinations of genes
Does not change the relative frequency of alleles in a population
Source #1: Gene Shuffling

11. Crossing over during meiosis produces variation in genes.
Gene shuffling
Crossing over during meiosis produces variation in genes.

12. Gene shuffling
Independent assortment allows alleles for one trait to segregate independently from alleles for another trait.

13. Gene shuffling
Independent assortment and crossing over produces variation in gametes, which produces variation in the family.

14. Don’t forget to chunk your notes!

15. Source #2: Law of Segregation

16. Law of segregation
Law of segregation happens when allele pairs from ___ & ___ separate and randomly unite during fertilization.
Mom
Dad
Mom/dad

17. Don’t forget to chunk your notes!

18. mutations
Change (mistake) in DNA code
Source #3: Mutations

19. mutations
A mutation is a
change/mistake
in the DNA

20. mutations
2 Types:
1. Gene Mutation
2. Chromosome Mutation

21. Gene Mutation: small change

22. Example: Point Mutation
mutations
Example: Point Mutation
Base is substituted
Will/won’t change protein
Organism is affected if the protein changes

23. Point mutations change one (or a few) _____ .
genes
genes
Point mutations change one (or a few) _____ .

24. Chromosomal Mutation: big change
mutations
Chromosomal Mutation: big change

25. Example: Frame-Shift Mutation
mutations
Example: Frame-Shift Mutation
Nucleotide deleted/added
Shift
Changes protein and affects organism

26. mutations chromosomes
Chromosomal mutations change the number or structure of ______________ .

27. mutations
4 Types:
Deletion
Duplication
Inversion
Translocation

28. Mutations can cause changes in the DNA.

29. Sometimes mutations can cause damage to cells that control growth.

30. Cells can lose control and _____ can spread to the whole body .
mutations
Cells can lose control and _____ can spread to the whole body .
cancer
cancer

31. mutations
Causes
Carcinogens
Viral infections
Radiation

32. Right now there is no cure for ______ .
mutations
Right now there is no cure for ______ .
cancer
cancer