1. Why do we look the way we do?
Genetics
Why do we look the way we do?

2. Inheritance of chromosomes
Egg + sperm  zygote
egg
meiosis
zygote
mitosis & development
sperm
fertilization

3. Inheritance of genes
On the chromosomes passed from Mom & Dad to offspring are genes
may be same information
may be different information
eye color
(blue or brown?)
eye color
(blue or brown?)

4. Effect of genes _________________________________

5. Genes affect what you look likeX Bb Bb BB Bb Bb bb
Where did the blue eyes go??

6. Genes affect what you look like…X Bb Bb BB Bb Bb bb
Why did the blue eyes stay??

7. Genes affect what you look like…X Bb Bb BB Bb Bb bb
Where did the blue eyes come from??

8. What did we show here? Traits come in “versions”
brown vs. blue eye color
__________________
Traits are inherited as separate units
brown & blue eye colors are separate & do not blend
brown x blue ≠ brown-blue eyes
Some traits mask others
brown eye colors masked blue

9. Paired chromosomes Paired chromosomes have same kind of information
 same types of genes
eye color
(blue?)
eye color
(brown?)
hair color
hair color

10. Traits are inherited as separate units
For each trait, an organism inherits 2 copies of a gene, 1 from each parent
a ____________ organism inherits 1 set of chromosomes from each parent
____________ = 2 sets of chromosomes
1 from Mom
__________________
1 from Dad

11. Making gametes Remember meiosis! B BB b BB = brown eyes
This all can be expressed using letters
flower color = P or p bb b
BB = brown eyes
bb = blues eyes
Bb = brown flower Bb B b
Remember meiosis!

12. How do we say it? B BB 2 of the same ________________ BB = brown eyes
bb = blues eyes bb b
2 different
________________ Bb B b
Bb = brown flower

13. Punnett squares
_________________
male / sperm
female / eggs

14. Genetics vs. appearance
There can be a difference between how an organism looks & its genetics
appearance or trait = ___________
brown eyes, blue eyes
genetic makeup = ___________
BB, bb, Bb
2 organisms can have the same appearance but have different genetics: BB vs Bb

15. Genetics vs. appearance
How were these brown eyes made?
eye color
(brown)
eye color
(brown)
eye color
(brown)
eye color
(blue)
vs. BB B Bb B b

16. Woof! Woof! Any Questions?