Transcript or mmbb To figure out what their kids could look like, we must do a

Let’s Review- Harry Potter Genetics
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-
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
Given the punnet squares for the parents, the
only possible genotype for Harry is Bb
Question 2: Harry marries Ginny who has red hair. What are
the possible Genotypes of their children’s hair?
First: what are the genotypes for
Harry and Ginny’s hair color?
Harry is: Bb
Ginny is: bb
Given the genotypes of Bb
and bb, we can fill in the
Punnet Square
Their
children
have a 50%
chance of
having red
hair or
brown hair
• Bb
Bb
• bb
bb
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
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
So let’s look at the possible genes for their children!
They have 3: Lily Luna, James Sirius and
Albus Severus
Let’s review the genes for Muggles ,
Magic, Brown hair and Red hair
M= muggleness
m= magic ability
B = brown hair
b= red hair
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
To figure out what their kids
could look like, we must do a
dihybrid cross
• Harry is mmBb
• Factor out the possibilities
Harry can give off the following traits:
1. Take the little m and put it with the
B (this is one possibility)
• mmBb
mB
To figure out what their kids
could look like, we must do a
dihybrid cross
• Harry is mmBb
• Factor out the possibilities
Harry can give off the following traits:
1. Take the little m and put it with
the B (this is one possibility)
2. Take the little m and put it with
the little b
• 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
Harry can give off the following traits:
1. Take the little m and put it with
the B (this is one possibility)
2. Take the little m and put it with
the little b
3. Go to the second little m and put
it with B
• mmBb
mB
mb mB
To figure out what their kids
could look like, we must do a
dihybrid cross
Harry can give off the
following traits:
1. Take the little m and
put it with the B (this is
one possibility)
2. Take the little m and
put it with the little b
3. Go to the second little
m and put it with B
4. Finally take the m and
put it with the b
We do this because we
must “factor” all the
possibilities
• Harry is mmBb
• 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
Ginny can give off the following traits:
1. Take the little m and put it with the
b (this is one possibility)
• mmbb
mb
To figure out what their kids
could look like, we must do a
dihybrid cross
Ginny can give off the
following traits:
1. Take the little m and
put it with the b (this is
one possibility)
2. Take the little m and
put it with the little b
3. Go to the second little
m and put it with b
4. Finally take the m and
put it with the b.
Ginny can only give
recessive genes
• Ginny is mmbb
• Factor out the possibilities
• mmbb
mb
mb mb
mb
Now let’s add a Punnet square! This one must be 16
squares to account for every possibility
If Harry had mB, mb, mB, mb to give we must place it at
the top to account for his genes
•
mB
mb
mB
mb
If Ginny had mb, mb, mb, mb to give we must place it
on the sides to account for her genes
•
mb
mb
mb
mb
mB
mb
mB
mb
Now let’s factor all these together!
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
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
To have no magic, there must be at least ONE big M!
Are there any here?
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
NOPE!!!!!!
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
So our only possibilities are magic and brown
hair and magic and red hair
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
To have Brown hair, there must be at least one
B! How many are here?
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
There are 8 Magic and Brown hair
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
To have red hair, there must be 2 little b’s! How
many are here?
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
There are 8 magic and red hair
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
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
Now we need to determine the
% of genotypes
Go back to the squares and
count all the possible
genotypes
:
Start with the first box: the genotype is mmBb. How
many do you see in the whole square?
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
8 of them are mmBb!!
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
How many of them are mmbb?
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
There are 8 mmbb
•
mB
mb
mb mmBb mmbb
mb mmBb mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb mmBb mmbb
mmBb
mb mmBb mmbb mmBb
mmbb
mmbb
So genotypically Harry and
Ginny would have
possibilities of :
8 mmBb
And
8 mmbb
Or we could say a 50%
chance of each
Now let’s Practice!!!!
With Harry Potter of course!!!!
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?
As determined before, what are
Ron’s and Hermione’s phenotypes?
Ron is magic and red hair
Hermione is magic and red hair
Ron and Hermione are pure recessive, so they have the
same genotype: mmbb
•
mb
mb
mb
mb
mb
mb
mb
mb
Now let’s factor all these together!
•
mb
mb
mb mmbb mmbb
mb mmbb mmbb
mb
mmbb
mmbb
mb
mmbb
mmbb
m
mb mmbb mmbb
mmbb
mb mmbb mmbb mmbb
mmbb
mmbb
So Ron and Hermione
kids, based on the Punnet
square
100% will
have
magic
and be
red
haired!
Question 2: Hermione gets put under a spell and marries Dudley.
What are the chances their kids will have magic and red hair?
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
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
So let’s use MMBB first for Dudley and
Hermione is mmbb
•
MB
MB
mb MmBb MmBb
mb MmBb MmBb
MB
MmBb
MmBb
MB
MmBb
MmBb
m
mb MmBb MmBb
MmBb
mb MmBb MmBb MmBb
MmBb
MmBb
So 100% of their kids would be
Muggles with Brown hair
Or MmBb
Now let’s use MmBb for Dudley and Hermione is
mmbb
•
MB
Mb
mb MmBb Mmbb
mb MmBb Mmbb
mB
mmBb
mmBb
mb
mmbb
mmbb
m
mb MmBb Mmbb
mmBb
mb MmBb Mmbb mmBb
mmbb
mmbb
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)