1. Let’s Review- Harry Potter Genetics

2. Question 1
Harry has dark brown hair like his father, but his mom had red hair. Using the genotypes of B and b, what possible genotypes does each of the Potters have?
The phenotypes of the Potters are:
James Potter-
Lily Potter-
Harry Potter-

3. Mom could be bb Dad could be BB or Bb
Using the genotypes of BB, Bb, bb, what are possible genotypes for Harry’s parents? Mom could be (she has red hair) Dad could be (he has dark brown hair)
Mom could be bb
Dad could be BB or Bb

4. Given the punnet squares for the parents, the only possible genotype for Harry is Bb

5. Question 2: Harry marries Ginny who has red hair
Question 2: Harry marries Ginny who has red hair. What are the possible Genotypes of their children’s hair?

6. First: what are the genotypes for Harry and Ginny’s hair color?
Harry is: Bb
Ginny is: bb

7. Given the genotypes of Bb and bb, we can fill in the Punnet Square
Bb Bb
bb bb
Their children have a 50% chance of having red hair or brown hair

8. How can Harry help us learn about Dihybrid Squares?
Dihybrid squares are punnet squares that look to compare 2 traits and see how they could be inherited

9. Keep in mind that the traits do not have to be inherited together Remember the Law of Independent Assortment
Just because Harry has brown hair does not mean he will have magic
Just because Ginny has red hair doesn’t mean that she will magic

10. So let’s look at the possible genes for their children!
They have 3: Lily Luna, James Sirius and Albus Severus

11. Let’s review the genes for Muggles , Magic, Brown hair and Red hair
M= muggleness
m= magic ability
B = brown hair
b= red hair

12. We have already determined the phenotypes for Harry and Ginny
Harry is mm for magic and Bb for brown hair… or mmBb
Ginny is mm for magic and bb for red hair….or mmbb

13. Factor out the possibilities mmBb mB
To figure out what their kids could look like, we must do a dihybrid cross
Harry is mmBb
Factor out the possibilities
mmBb mB
Harry can give off the following traits:
1. Take the little m and put it with the B (this is one possibility)

14. Factor out the possibilities mmBb mB mb
To figure out what their kids could look like, we must do a dihybrid cross
Harry is mmBb
Factor out the possibilities
mmBb
mB mb
Harry can give off the following traits:
Take the little m and put it with the B (this is one possibility)
Take the little m and put it with the little b

15. Factor out the possibilities mmBb mB mb mB
To figure out what their kids could look like, we must do a dihybrid cross
Harry is mmBb
Factor out the possibilities
mmBb
mB mb mB
Harry can give off the following traits:
Take the little m and put it with the B (this is one possibility)
Take the little m and put it with the little b
Go to the second little m and put it with B

16. Factor out the possibilities mmBb mB mb mB mb
To figure out what their kids could look like, we must do a dihybrid cross
Harry is mmBb
Factor out the possibilities
mmBb
mB mb mB mb
Harry can give off the following traits:
Take the little m and put it with the B (this is one possibility)
Take the little m and put it with the little b
Go to the second little m and put it with B
Finally take the m and put it with the b
We do this because we must “factor” all the possibilities

17. Factor out the possibilities mmbb mb
To figure out what their kids could look like, we must do a dihybrid cross
Ginny is mmbb
Factor out the possibilities
mmbb mb
Ginny can give off the following traits:
1. Take the little m and put it with the b (this is one possibility)

18. Factor out the possibilities mmbb mb mb mb mb
To figure out what their kids could look like, we must do a dihybrid cross
Ginny is mmbb
Factor out the possibilities
mmbb
mb mb mb mb
Ginny can give off the following traits:
Take the little m and put it with the b (this is one possibility)
Take the little m and put it with the little b
Go to the second little m and put it with b
Finally take the m and put it with the b.
Ginny can only give recessive genes

19. Now let’s add a Punnet square
Now let’s add a Punnet square! This one must be 16 squares to account for every possibility

20. If Harry had mB, mb, mB, mb to give we must place it at the top to account for his genes

21. If Ginny had mb, mb, mb, mb to give we must place it on the sides to account for her genes

22. Now let’s factor all these together!
mB mb mB mb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb m

23. Now we need to determine the % of phenotypes
Go back to the squares and count all the possible phenotypes:
We know that the following possibilities could occur:
No magic, brown hair
No magic, red hair
Magic, brown hair
Magic, red hair

24. mB mb mB mb mb mmBb mmbb mmBb mmbb mb mmBb mmbb mmBb mmbb
To have no magic, there must be at least ONE big M! Are there any here?
mB mb mB mb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb m

25. NOPE!!!!!! mB mb mB mb mb mmBb mmbb mmBb mmbb mb mmBb mmbb mmBb mmbb

26. So our only possibilities are magic and brown hair and magic and red hair
mB mb mB mb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb m

27. To have Brown hair, there must be at least one B! How many are here?
mB mb mB mb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb m

28. There are 8 Magic and Brown hair
mB mb mB mb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb m

29. To have red hair, there must be 2 little b’s! How many are here?
mB mb mB mb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb m

30. There are 8 magic and red hair
mB mb mB mb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb m

31. So phenotypically Harry and Ginny would have possibilites of :
8 magic and brown haired kids
And
8 magic and red haired kids
Or we could say a 50% chance of each

32. Now we need to determine the % of genotypes
Go back to the squares and count all the possible genotypes:

33. mB mb mB mb mb mmBb mmbb mmBb mmbb mb mmBb mmbb mmBb mmbb
Start with the first box: the genotype is mmBb. How many do you see in the whole square?
mB mb mB mb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb m

34. mB mb mB mb mb mmBb mmbb mmBb mmbb mb mmBb mmbb mmBb mmbb
8 of them are mmBb!!
mB mb mB mb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb m

35. How many of them are mmbb?
mB mb mB mb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb
mb mmBb mmbb mmBb mmbb m

36. There are 8 mmbb mB mb mB mb mb mmBb mmbb mmBb mmbb

37. So genotypically Harry and Ginny would have possibilities of :
8 mmBb
And
8 mmbb
Or we could say a 50% chance of each

38. With Harry Potter of course!!!!
Now let’s Practice!!!!
With Harry Potter of course!!!!

39. Question 1: Hermione and Ron marry and have 2 kids (Rose and Hugo)
Question 1: Hermione and Ron marry and have 2 kids (Rose and Hugo). What are the chances that their kids have magic and red hair?

40. As determined before, what are Ron’s and Hermione’s phenotypes?
Ron is magic and red hair
Hermione is magic and red hair

41. Ron and Hermione are pure recessive, so they have the same genotype: mmbb
mb mb mb mb mb

42. Now let’s factor all these together!
mb mb mb mb
mb mmbb mmbb mmbb mmbb
mb mmbb mmbb mmbb mmbb
mb mmbb mmbb mmbb mmbb
mb mmbb mmbb mmbb mmbb m

43. So Ron and Hermione kids, based on the Punnet square
100% will have magic and be red haired!

44. Question 2: Hermione gets put under a spell and marries Dudley
Question 2: Hermione gets put under a spell and marries Dudley. What are the chances their kids will have magic and red hair?

45. We already know the following about Hermione:
She has red hair so she must be bb
She can do magic so she must be mm

46. Now Dudley is a different story:
We know that he has Brown hair so he could be BB or Bb
We know that he can not do magic so he is either MM or Mm

47. So let’s use MMBB first for Dudley and Hermione is mmbb
MB MB MB MB
mb MmBb MmBb MmBb MmBb
mb MmBb MmBb MmBb MmBb
mb MmBb MmBb MmBb MmBb
mb MmBb MmBb MmBb MmBb m

48. So 100% of their kids would be
Muggles with Brown hair
Or MmBb

49. Now let’s use MmBb for Dudley and Hermione is mmbb
MB Mb mB mb
mb MmBb Mmbb mmBb mmbb
mb MmBb Mmbb mmBb mmbb
mb MmBb Mmbb mmBb mmbb
mb MmBb Mmbb mmBb mmbb m

50. In this case, the kids would be
25% Muggle with brown hair (MmBb)
25% Muggle with red hair
25% Magic with brown hair
25% Magic with red hair (mmbb)