1. Monday April 3, 2017 I can: Agenda HW: IP: EOC Grab Bag (10) Catalyst
predict offspring of incomplete dominant crosses
Agenda
(10) Catalyst
(25) GN: Incomplete Dominance
(10) GP: Spongebob Genetics
(15) IP: EOC Grab Bag (5) Exit Ticket
(20) Trashketball: Review Cells and Organelles
Catalyst
In rabbits, brown fur color is dominant to white. What offspring can be expected from crossing a heterozygote with a white one? Show all steps.
What does it mean for an allele to be dominant? (Hint: it doesn’t just have to do with the fact it’s capitalized).
HW: IP: EOC Grab Bag

2. Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes.

3. Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes.

4. Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes.

5. Some alleles are neither dominant nor recessive, and many traits are controlled by multiple alleles or multiple genes.
complete dominance
incomplete dominance
co-dominance
multiple alleles
sex-linked

6. R = red W = white RR RW WW red pink white
Red + White = pINC
INComplete dominance!
Incomplete dominance is a pattern of inheritance in which neither allele is completely dominant over the other. The heterozygous phenotype is somewhere in between the two homozygous phenotypes.
we CAN use two different letters to represent the different alleles
In incomplete dominance, there are always 3 phenotypes. One is in the middle of the other two.
R = red
W = white RR RW WW
genotype:
red
pink
white
phenotype:

7. ? BB black B = black W = white
Coat color in mice exhibits incomplete dominance. ? BB
black

8. ? WW white B = black W = white
Coat color in mice exhibits incomplete dominance. ? WW
white

9. ? BW gray B = black W = white
Coat color in mice exhibits incomplete dominance. ? BW
gray

10. R = red
W = white
Flowers exhibit incomplete dominance for petal color. ? RR
red

11. R = red
W = white
Flowers exhibit incomplete dominance for petal color. ? WW
white

12. R = red
W = white
Flowers exhibit incomplete dominance for petal color. ? RW
pink

13. T = tall
S = short
Human height follows a pattern of incomplete dominance. ? TT
tall

14. ? SS short T = tall S = short
Human height follows a pattern of incomplete dominance. ? SS
short

15. ? medium height TS T = tall S = short
Human height follows a pattern of incomplete dominance. ?
medium height TS

16. Scale color in fish is controlled by two incompletely dominant alleles
Scale color in fish is controlled by two incompletely dominant alleles. The homozygotes are blue and yellow. What are the genotypes for blue, yellow, and green fish?
blue –
yellow –
green –

17. Wing color in birds is controlled by two incompletely dominant alleles
Wing color in birds is controlled by two incompletely dominant alleles. The homozygotes are blue and red. What are the genotypes for blue, red, and purple birds?
blue –
red –
purple –

18. Tooth number in Zorgs is controlled by two incompletely dominant alleles. The homozygotes have 2 and 4 teeth. What are all possible genotypes of Zorgs?
2 teeth –
4 teeth –
?? teeth –

19. Solving an Incomplete Dominance Problem
Coat color in mice is incompletely dominant. Yellow and white-colored mice are homozygous, while cream-colored mice are heterozygous. If two cream-colored mice mate, what phenotypic ratio can we expect of their offspring?
Y = yellow; W = white
Solving an Incomplete Dominance Problem Y W
1. Read the problem. Underline the known alleles. Identify the type of inheritance as incomplete dominance. Y W Y Y Y
2. Choose a letter to represent each allele in the problem.
3. Circle and/or write down the genotypes of the parents. Y W W W W
4. Set up and solve Punnett Square.
5. Highlight and answer what the question is asking.
parents: YW x YW
yellow =
1/4 =
25%
white=
1/4 =
25%
cream =
2/4 =
50%

20. What type of inheritance? (Complete or Incomplete Dominance)
Tall pea plants are crossed with short pea plants. All the offspring are tall.
How do you know what type of inheritance it is?

21. What type of inheritance? (Complete or Incomplete Dominance)
Having 10 fingers is dominant to having 12 fingers. A woman with 12 fingers has a child with a normal man and all their children have 10 fingers.
How do you know what type of inheritance it is?

22. What type of inheritance? (Complete or Incomplete Dominance)
A blue butterfly mates with a yellow butterfly. All their children are green.
How do you know what type of inheritance it is?

23. What type of inheritance? (Complete or Incomplete Dominance)
You have a black horse and a white horse on your farm. They have babies, and they’re all gray.
How do you know what type of inheritance it is?

24. What type of inheritance? (Complete or Incomplete Dominance)
You have a black horse and a white horse on your farm. They have babies, and they’re all black.
How do you know what type of inheritance it is?