 HAPPY FRIDAY 
A3
Computer
Bellwork:
Complete CoDominant Punnett Square in your bellwork page
In rabbits, white coat color (CW) and black coat color (CB) are codominant; heterozygotes (CBCW) are spotted.
Draw a Punnett Square that shows the phenotypes of the offspring
from a heterozygous spotted rabbit and a homozygous white-coated
rabbit?
Small Group
CHAMPS
Shoulder Partner
In rabbits, white coat color (CW) and black coat color (CB) are co-dominant; heterozygotes (CBCW) are spotted.
Draw a Punnett Square that shows the phenotypes of the offspring from a heterozygous spotted rabbit and a homozygous
white-coated rabbit?
CB= Black
CW = White
CBCW = Black with White Spots
Dad = CBCW
Mom = CWCW
B
C
W
C
W
C
CBCW
CW CW
W
C
B
W
C C
W
W
C C
0% Black
50% Black with White Spots
50% White
Collect Today
NOTHING!
Assigned
6th and 7th Period - Final Exam Review Notecard (Day of Final)
Genetics MAKE-UP Quiz (Monday)
Page 77 – Family Tree Project Part 2 – Include Rubric and
Punnett Squares (Monday)
Genetics Exam (Monday)
Genetics Vocabulary MAKEUP Quiz (WEDNESDAY)
Biolo-Tree Extra Credit (Wednesday)
Late
Page 82 – Bikini Bottom Genetics (-50%)
Page 85 – Incomplete Practice (-30%)
Finals Schedule
•Monday – Normal Day
•Tuesday – 7th Period Finals/No 6th Period
st
th
th
•Wednesday – 1 and 6 Period Finals/No 7
Period
•Thursday (1/2 Day) – 5th and 2nd Period Finals
rd
th
•Friday (1/2 Day) – 3 and 4 Period Finals
Genetics Review Mini-Quiz
You need a piece of notebook
paper, go to your lab station
and answer the following
questions. Only 2 people per
piece of paper.
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
What is a genotype?
A man is heterozygous for a trait. Will the dominant or recessive trait be expressed? Why?
What does it mean if a woman is homozygous recessive? Using the letter “B,” write her genotype.
What is a phenotype?
Long eyelashes (E) are dominant to short eyelashes (e). A heterozygous woman is crossed with a homozygous dominant man. What
is the percent chance their offspring will have short eyelashes? (Must draw a Punnett square)
What does homozygous mean? Write an example.
What does heterozygous mean? Write an example.
What does it mean if a gene is expressed?
What does a dihybrid cross show?
What was Mendel’s predicted phenotypic ratio for a typical dihybrid cross?
Hazel eyes (H) are dominant to green eyes (h). A homozygous dominant man is crossed with a homozygous recessive woman. What
is the percent chance their offspring will have green eyes? (Must draw a Punnett square!)
Turnip color is controlled by a gene that exhibits incomplete dominance; purebred red turnips (RR) crossed with purebred white
turnips (WW) make purple turnips(RW). What are the chances of producing white offspring when you cross two purple parents?
If a man with heterozygous type B blood (BO) marries a woman with type AB blood, what is the probability that they will have child
with blood type B?
When an orange lily (L) is crossed with a white lily (W) , a cream-colored lily (LW) will result. What is the probability of producing
cream-colored lilies from two cream-colored parents?
In humans, the gene for baldness (h) is recessive. This gene is located on the X chromosome but not on the Y chromosome. A man
who is bald has a child with a woman who is heterozygous for baldness, but is not bald. What is the probability that…..
a.
A female child will be a carrier?
b.
A male child will be normal?
c.
A female child will develop the trait for baldness?
d.
A male child will develop the trait for baldness?
Direct
Instruction
CHAMPS
Essential Question
PG 83
What are sex-linked
traits and how are they
modeled?
Standard
B6F - Predict possible outcomes of genetic combinations such as
Non-Mendelian Genetics.
Today we’re going to talk about a special case:
sex-linked traits
• Remember: Each person
inherits an X chromosome from
mom and either an X or a Y
from dad
• We use the letters X and Y to
represent chromosomes (not
alleles)
Sex-linked traits
• Are traits that are determined by either the Y or
X chromosome
• If they are determined by the Y chromosome they
are referred to as “Y-linked”
• Y-linked disorders are very rare and often cause
infertility in men
• If they are determined by the X-chromosome they
are referred to as “X-linked”
X-Linked Traits
X-Linked Dominant:
• These conditions (such as vitamin D
resistant rickets) are rare and can
affect both men and women
• Men are more affected than women
• Both men and women can pass on
the affected chromosome to their
children
X-Linked Recessive:
• These disorders (such as hemophilia
and color blindness) more frequently
affect men than women
• Both men and women can pass these
traits on to their children (at different
rates)
• An affected man/unaffected woman = sons
who are unaffected, daughters who are
carriers
• An affected woman/unaffected man = 50%
chance of passing the trait. If she passes on
her affected X chromosome, then her
daughters will be carriers and her sons will
be affected
• This is why men are more likely to be color
blind than women
X-Linked
Recessive
(carrier
mother)
Mrs. PigglyWiggly is a carrier of the sex-linked hemophilia allele, and Mr. PigglyWiggly is
normal (as far as blood chemistry goes).
Draw a Punnet square that shows the theoretical genotypes and phenotypes among their
children.
X
Y
XX
XY
H = hemophilia
XX = FEMALE
XY = MALE
Mom =XHX
Dad = XY
X
carrier female (XHX) 25%; normal female (XX) 25%;
hemophilia male (XHY) 25%; normal male (XY) 25%
Practice
Problems
Table Group
1. In fruit flies (Drosophila), one eye color gene is x-linked, with a recessive white
allele and a dominant red allele. If white-eyed female flies were bred to red-eyed
male flies, what would be the expected offspring (assume all parental flies are
purebred)?
Red-eyed females (XRXr) 50%;
White-eyed males (XrY) 50%
Shoulder Partner
2. Earl has normal color vision, while his wife Erma is colorblind. Colorblindness
is an X-linked trait, and the normal allele is dominant over the colorblindness allele.
If they have a large family, in what ways should the colorblindness affect their
children?
Female Carriers (XXC) 50%;
Colorblind Males (XCY) 50%
Independent
3. Ethan is colorblind. His wife, Edna, is homozygous for the normal color vision
allele. If they have eight children, what percentage of them would you expect to be
colorblind. Show a Punnett square and list genotypic and phenotypic ratios.
Female Carriers (XXC) 50%;
Normal Males (XY) 50%
1.
2.
3.
4.
5.
6.
7.
8.
9.
10.
11.
12.
13.
14.
15.
What is a genotype? The genes (letters) that determine a phenotype
A man is heterozygous for a trait. Will the dominant or recessive trait be expressed? Why? Dominant because dominant covers recessive
What does it mean if a woman is homozygous recessive? Using the letter “B,” write her genotype. Both of her genes are recessive (bb)
What is a phenotype? The physical characteristics of an organism
Long eyelashes (E) are dominant to short eyelashes (e). A heterozygous woman is crossed with a homozygous dominant man. What is the
percent chance their offspring will have short eyelashes? (Must draw a Punnett square) 0%
What does homozygous mean? Write an example. Homozygous means the same letters are present Ex. BB or bb
What does heterozygous mean? Write an example. That the genes are different Ex. Bb
What does it mean if a gene is expressed? The phenotype for that gene is seen (dominant)
What does a dihybrid cross show? Genetic possibilities for 2 traits
What was Mendel’s predicted phenotypic ratio for a typical dihybrid cross? 9:3:3:1
Hazel eyes (H) are dominant to green eyes (h). A homozygous dominant man is crossed with a homozygous recessive woman. What is the
percent chance their offspring will have green eyes? (Must draw a Punnett square!) 0%
Turnip color is controlled by a gene that exhibits incomplete dominance; purebred red turnips (RR) crossed with purebred white turnips
(WW) make purple turnips(RW). What are the chances of producing white offspring when you cross two purple parents? 25%
If a man with heterozygous type B blood (BO) marries a woman with type AB blood, what is the probability that they will have child with
blood type B? 50%
When an orange lily (L) is crossed with a white lily (W) , a cream-colored lily (LW) will result. What is the probability of producing creamcolored lilies from two cream-colored parents? 50%
In humans, the gene for baldness (h) is recessive. This gene is located on the X chromosome but not on the Y chromosome. A man who is
bald has a child with a woman who is heterozygous for baldness, but is not bald. What is the probability that…..
a.
A female child will be a carrier? 25%
b.
A male child will be normal? 25%
c.
A female child will develop the trait for baldness? 25%
d.
A male child will develop the trait for baldness? 25%