1. Get ready for : New Info
GENETICS WITH A SMILE

2. OBJECTIVES: what are we going to learn?
Define dominant and recessive traits
Explain: homozygous
heterozygous
genotype
phenotype

3. Here’s what you’ll be doing
Creating your Smiley Face offspring:
1. flip coins to determine their physical
traits.
2. match traits on sheet to determine
what your offspring look like.
3. flip coins to determine male or female.
4. sketch Smiley; in Tech class you will use Word to computer generate sketch.

4. Remember? Genes are…not these! Where do they come from?
How many does each cell have?
Where do we find them?

5. Genes Dominant gene-one that always shows up.
Write it as a capital letter;
example: B for brown hair
Recessive gene-one that is hidden when the other copy of the gene contains a dominant trait. Only shows up when there is no dominant gene present.
Write it as a lower case letter;
example: b for blond hair

6. What if?
What if an offspring inherits one dominant gene from their mother and one dominant gene from their father? Example: BB for brown hair We call that being HOMOZYGOUS dominant because you have two genes that are the same. Two capital letters!

7. Remember: Homozygous Dominant is:
Both the same trait from parents that always shows up
use capital letter
Brown hair from mother B
Brown hair from father B

8. What if?
What if an offspring inherits one recessive gene from their mother and one recessive gene from their father?
Example: bb for blond hair
We call that being homozygous recessive. Two genes the same; use lower case.

9. Remember: Homozygous Recessive is:
Both same trait but doesn’t show up if dominant trait is present.
blond hair from mother b
blond hair from father b bb

10. I know what you’re going to ask!
What if an offspring inherits one dominant gene from one parent and one recessive gene from the other parent?
Example: Bb
What do you think we would call this?

11. Heterozygous Dominant!! Bb

12. BB bb Bb So what is a genotype?
Those capital and lower case letters you just learned about…tell what your genes are. BB bb Bb

13. So what is phenotype?
Those physical traits that you inherited from your parents:
Brown hair
Blue eyes
Red nose…oops, sorry!
Right handedness
Color blindness
Straight hairline

14. Create your Smiley face
2 pennies; 1 for each parent; male-female
PENNIES ARE MARKED M AND F
1. Flip both coins at the same time for each trait on your sheet.
2. HEADS= DOMINANT TRAIT
TAILS= RECESSIVE TRAIT
3. Circle the capital or lower case letter on your sheet.

15. 4. Write in the Genotype…CC, cc, Cc
5. Write in the Phenotype…oval face, round head.
look at the Smiley Face Traits sheet.
6. This will help you create your Smiley face sketch.
7. You will recreate this sketch on your laptop in Tech class.

16. Look familiar?
Traits are contained in our genes; also referred to as ALLELLES