Transcript Genetics Review

Question #1
What does the term phenotype
mean?
Answer:
How a trait appears/looks
Question #2
What does the term genotype
mean?
Answer:
The group of genes that make up
a trait (the letters)
Question #3
What does a capital letter mean?
Answer:
It means the allele is dominant
Question #4
If an allele is recessive how many
copies of the allele are needed
for it to be expressed?
Answer:
Two copies
(aa-one from mom and one from dad)
Question #5
What type of alleles are known as
‘loud and bossy’?
Answer:
Dominant alleles
Question #6
Purple flowers (P) are dominant to
white flowers. Write the
genotype of a heterozygous
purple flower.
Answer:
Pp
Question #7
Purple flowers (P) are dominant to
white flowers. If a white flower
is crossed with a heterozygous
purple flower, what is the chance
of having white flowers?
p
P
Answer: 50%
p Pp
pp
p
pp
Pp
Question #8
Purple flowers (P) are dominant to
white flowers. If two
heterozygous flowers are
crossed, what is the chance of
having white flowers?
p
P
Answer: 25%
P PP
Pp
p
pp
Pp
Question #9
Is AA, heterozygous, homozygous
dominant or homozygous
recessive?
Answer: homozygous dominant
Question #10
If red colored dragons are
dominant to orange colored
dragons what is the phenotype for
a dragon who is Rr?
Answer: Red
Question #11
If red colored dragons are
dominant to orange colored
dragons what is the genotype for
a dragon who is orange (use R)?
Answer: rr
Question #12
What is another name for
homozygous?
Answer: Purebred
Question #13
What is another name for hybrid?
Answer: Heterozygous
Question #14
In Oompa Loompahs, gray faces
(G) are dominant to orange. If a
homozygous gray faced male
married a heterozygous gray
female and they have 6 kids,
about how many will have gray
G
G
faces?
G GG GG
Answer: All 6
g Gg
Gg
Question #15
Two heterozygous Oompahs are
crossed. What proportion of the
offspring will have orange faces?
Answer: 25%
G
g
G GG Gg
g Gg
gg
Question #16
In a certain type of fish there are
three possible alleles; red, orange, and
yellow. Orange is the intermediate of
red and orange. Assuming red is R and
yellow is Y, what is the genotype for
the orange fish?
Answer: RY
Question #17
In these same fish where
RR- Red, RY- Orange, and YY- Yellow,
what are all of the possible
phenotypes of an orange fish is mated
with a yellow fish?
R
Y
RY
YY
Y RY
YY
Answer: orange and yellow Y
Question #18
In these same fish where
RR- Red, RY- Orange, and YY- Yellow,
what are all of the possible genotypes
if two orange fish are mated?
Answer: RR, RY, YY
R
Y
R RR
RY
Y RY
YY
Question #19
In these same fish where
RR- Red, RY- Orange, and YY- Yellow,
what are the chances of having yellow
fish if a red fish is mated with a
yellow fish?
Answer: 0%, all would be
orange
R
R
Y RY
RY
Y RY
RY
Question #20
R is red and W is white in 4 o’clocks.
If a pink flower is crossed with a red
flower what are the chances of
getting red flowers?
Answer: 50% chance
R
W
R RR RW
R RR RW
Question #21
In heffalumps, pink (P) and yellow (Y)
are equally dominant, the
heterozygote is spotted. If two
spotted heffalumps are mated, what
are the chances of getting the yellow
gene?
Answer: 25% chance
P
Y
P PP
PY
Y PY
YY
Question #22
In heffalumps, pink (P) and yellow (Y)
are equally dominant, the
heterozygote is spotted. If a pink
heffalump is mated with a spotted
heffalump, what are the changes of
getting the yellow gene?
Answer: 0% chance
P
Y
P PP
PY
P
PY
PP
Question #23
In some cattle the color roan is a
mixture of red (R) and white (W)?
What are the genotypes for the
following colors:
Red- ____ White- ____ Roan- __
Answer: RR, WW, RW
Question #24
In some cattle the color roan is a
mixture of red (R) and white (W)? If
a red cow and a white bull are mated,
what are the chances of having roan
babies?
Answer: 100%
R
R
W RW RW
W RW RW
Question #25
In humans, blood type is a classic
example of a trait inherited by
multiple alleles. What does multiple
alleles mean?
Answer: There are more than two
alleles for a trait (within a
population).
Question #26
In humans, blood type is a classic
example of a trait inherited by
multiple alleles. How many different
alleles are there?
Answer: 3
Question #27
In humans, blood type is a classic
example of a trait inherited by
multiple alleles. What are the three
alleles possible?
Answer: A, B, and O
Question #28
In humans, blood type is a classic
example of a trait inherited by
multiple alleles. How many alleles does
each person receive?
Answer: 2, one from mom and one
from dad
Question #29
Complete the following:
Blood Types ____ and ____ are
dominant over Type O
Answer: A and B
Question #30
Complete the following:
Blood Types ____ and ____ are
codominantly expressed, meaning they
are expressed together
Answer: A and B
Question #31
What blood type is known as the
universal donor and why?
Answer: Type O blood, because it
has no antigens on its surface and
therefore can be given to any
person
Question #32
What blood type is known as the
universal receiver and why?
Answer: Type AB blood, because
it will not react poorly to antigen
A or B and a person with this
blood type can receive a
tranfusion from anyone
Question #33
If a mother is homozygous for type A
blood and a father is heterozygous for
type B blood, what are the chances of
having a child with type O blood?
Answer: 0%
A
A
B AB AB
O AO AO
Question #34
If a mother has type B blood and her
son has type O blood is the mother
homozygous B or heterozygous B?
Answer: Heterozygous, because
he had to get one O from dad and
one O from mom
Question #35
A woman and her husband claim that
their child was mixed up on the hospital
because of its dark hair. The mother
has type B blood and the father has type
A blood. The alleged child has type O
blood. Should the parents be concerned?
Answer: No, the mom and dad could
both be heterozygous resulting in a
child with type O blood.
Question #36
• 1. A nonhemophiliac man marries a
nonhemophiliac woman whose father
was a hemophiliac. What kinds of
children can they have and in what
percentages?
Question #36
Step 1: Determine the letters you will use to
represent the alleles. For this one I chose “B”
for normal blood and “b” for the hemophiliac
gene.
Step 2: Determine the alleles of the parents.
The non-hemophiliac man must be XBY. The
non-hemophiliac woman with a hemophiliac
father must be XBXb, because she had to get Xb
from her afflicted father.
Step 3: Set up your Punnett square and do
the cross. Determine the genotypes and
expected percent of each type of child from
the cross.
Sex –Linked Genetics
Question #36
XB
Y
XB
XB X B
XB Y
Xb
XBXb
Xb Y
25% Normal girl
25% Normal boy
25% Carrier girl
25% Hemophiliac son
Question #37
Two normal-visioned parents have a
color-blind son. What are the genes of
the parents? What are the chances of
their having a color blind girl? Explain.
Question #37
Step 1 : Choose your alleles. I will use “C” for normal color vision and “c”
for the red/green color blind condition.
Step 2 : Determine the genotypes of the parents. Both parents have
normal vision, yet they have a color-blind son. Because, the dad can not
have the “c” allele (it’s sex-linked remember and he has normal vision)
the wife must be a carrier. Dad = XCY and Wife= XCXc
Step 3 : Set up your Punnett square and do the cross!
XC
Y
XC XCXC
XCY
C
c
XX
c
XY
c
X
There are no chances of this couple having a
color blind girl. The father would have to be
color blind to contribute the second defective
Xc allele needed to produce a color-blind
daughter.
Question #38
A normal-visioned man marries a normalvisioned woman whose father was colorblind. They have two daughters who grow
up and marry. The first daughter has five
sons, all normal-visioned. The second
daughter has two normal-visioned
daughters and a color-blind son. Diagram
the family tree, including the genes of all the
people mentioned.
Question #38
Step 1 : As this is another problem about color blindness, we already have our
alleles ready from the previous problem. “C” for normal vision, “c” for the
red/green color blind condition. Use what you know from the problem to assign
genotypes and do Punnett square crosses to help answer all the questions. A family
pedigree might be a great way to show clearly the genes of all the people
mentioned.
Step 2 : Figure out the genotypes of the parents. Both have normal vision, so
the man must be XCY . The woman’s father was color blind she has at least
one daughter who has a color blind son. That son had to get his Xc from his
mom who had to get it from her mom. So, the woman must be a carrier.
(XCXc)
Step 3 : Do the crosses. Explain the expected
genotypes of all the people involved.
XC
XC
Xc
Mom
Y
XCXC
XCXc
XCY
XcY
Grandpa
Dad
Xc
Y
XC
XCXc
XCY
XC
XCXc
XCY
These are their possible offspring. Mom’s dad was color
blind, so she got her Xc from him. (see cross above) The
problem says they had two daughters, so we will focus
on them. One daughter had 5 sons, all with normal
vision. She must not be the carrier daughter, otherwise
odds are she would have had a color-blind son. Do we
know if her husband is color blind or not? The other
daughter had 2 normal vision daughters and 1 colorblind son, so she must be a carrier of the Xc allele.
The first daughter would have the genotype, XCXC and all her sons
would be XCY and they would have normal vision. If her husband
was color- blind it would only effect their daughters, (50% would be
expected to be color-blind) but, because they had no daughters
we have no way of knowing from this information if he is color-blind
or not. (see grandpa to see a Punnett square for this situation.)
The second daughter would have to be the carrier. Her daughters have
normal vision. However, one or both of them could be carriers of the trait.
The son, however, was not so lucky and got the defective X. With no
second X to mask the effects, he will be color-blind.
XC
Y
XC
Normal
vision
Normal
vision
Xc
Carrier
Color-blind
son