1. Do now activity #2
Write down an example of homozygous dominant allele pairs.
Write down an example of homozygous recessive allele pairs.
Write down an example of heterozygous allele pairs.
Described the relationship shared between the genotype and the phenotype.

2. Essential Question: Section 4-2: alleles
How does the genotype of an organism determine the phenotype of that organism?
Learning Target
Distinguish between dominant and recessive traits.
Distinguish between heterozygous and homozygous genotypes.
Explain how the genotype of an organism results in the phenotype of the organism.
Section 4-2: alleles

3. announcements Section 4 Test Scheduled for this Friday: 6/15/18
Section 4 Stamp Sheet due Friday 6/15/18

4. Don’t forget to chunk your notes!

5. Alleles occur in pairs (2).
overview
Alleles occur in pairs (2).

6. We get one from ___ & one from ___ .
overview
Mom/dad
We get one from ___ & one from ___ .
Mom
Dad

7. Dominant traits are written with an __________ allele.
overview
Uppercase letter
uppercase
Dominant traits are written with an __________ allele.

8. Recessive traits are written with a ____________ allele.
overview
lowercase letter
Recessive traits are written with a ____________ allele.
lowercase

9. Don’t forget to chunk your notes!

10. ___________ alleles are the same.
Same or different
homozygous
___________ alleles are the same.
Homozygous

11. Homozygous _______ alleles are both capitalized.
Same or different
dominant
Homozygous _______ alleles are both capitalized.
dominant

12. Homozygous _______ alleles are both lowercase.
Same or different
recessive
Homozygous _______ alleles are both lowercase.
recessive

13. ___________ alleles are different.
Same or different
heterozygous
Heterozygous
___________ alleles are different.

14. Don’t forget to chunk your notes!

15. What we can physically see
now you see me…
Phenotype
What we can physically see

16. The genetic “code” we do not see
now you don’t!
Genotype
The genetic “code” we do not see

17. Don’t forget to chunk your notes!

18. Some alleles are not as simple as either dominant or recessive
Exceptions to the rule
Some alleles are not as simple as either dominant or recessive

19. Some alleles are neither dominant nor recessive
Exceptions to the rule
Some alleles are neither dominant nor recessive

20. Many traits are controlled by multiple alleles or genes
Exceptions to the rule
Many traits are controlled by multiple alleles or genes

21. Incomplete Dominance:
When one allele is not completely dominant over the other
Example:
RR = red flower
rr = white flower
Rr = pink flower
The exceptions

22. When both alleles contribute to phenotype
Codominance:
When both alleles contribute to phenotype
Example:
RR = red flower
rr = white flower
Rr = red & white flower
The exceptions

23. when more than two alleles contribute to the phenotype
Multiple Alleles:
when more than two alleles contribute to the phenotype
Example:
Blood type A
Blood type B
Blood type AB
Blood type O
The exceptions

24. Many traits produced by the interaction of several genes
The exceptions
Polygenic Traits:
Many traits produced by the interaction of several genes
Examples:
Hair color
Eye color
Height