1. Do now activity #7
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 5-4: 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 5-4: Genetic variation

3. Last day to turn in LATE WORK is tomorrow.
announcements
Biology Tutoring this week:
Lunch B (Tuesday & Thursday)
7:00AM (Monday – Friday)
After school Biology Tutoring: Tuesday
Last day to turn in LATE WORK is tomorrow.

4. announcements Available Extra Credit: Tissue Box = 2 Points
Color Printer Paper = 10 Points Plastic Pencil Box = 5 Points

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. 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

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

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

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

13. Source #2: Law of Segregation

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

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

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

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

18. Gene Mutation: small change

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

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

21. Chromosomal Mutation: big change
mutations
Chromosomal Mutation: big change

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

23. mutations
chromosomes
Chromosomal mutations change the number or structure of ___ .

24. mutations
4 Types:
Deletion
Duplication
Inversion
Translocation

25. Mutations can cause changes in the DNA.

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

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

28. mutations
Causes
Carcinogens
Viral infections
Radiation

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