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Biology Chapter 7
Beyond Mendel Notes
Phenotype: _________________________________________________________________
Genotype: ___________________________________________________________________
What is Mendelian inheritance controlled by?
Incomplete Dominance:
______________________________________________________________________________
_____________________________________________________________________________.
Example of Incomplete Dominance:
______________________________________________________________________________
Example Number 2
When green betta fish (B1B1) are crossed with a steel blue betta fish (B2B2) all the offspring have
the heterozygous genotype (B1B2).
These offspring will be royal blue in color.
Practice Problem: What is the phenotypic ratio with two royal blue betta fish are crossed?
Practice Problems:
The petal color of four o’clocks (flowering plants) is inherited by incomplete dominance. Plants
with R1R1 genes have red flowers. Plants with R2R2 genes have white flowers. Plants with R1R2
genes have pink flowers.
1. Joey planted snapdragons in his garden. All the seeds came from one set of parent plants.
When the flowers bloomed, Joey saw that all of his flowers were pink. What are the genotypes of
the parent plants? Include a punnett square in your answer.
Genotype of the parents: ___________________ and _______________________
2. Kory also planted snapdragons in his garden. All of his seeds came from one set of parents.
When his plants bloomed, 50% were white and 50% were pink. What are the genotypes of the
parent plants? Include a punnett square in your answer.
Genotype of the parents: ___________________ and _______________________
3. Casie, Zach, and Kelly each have beautiful gardens of snapdragon flowers. Casie has a
garden of red snapdragons and would like to create a new section to her garden including only
pink four snapdragons. Zach breeds only pink snapdragons and Kelly breeds white snapdragons.
From whose garden will Casie have the greatest probability of creating a pink population of
snapdragons flowers? Create two punnett squares to prove your point.
Casie’s Flowers x Zach’s Flowers
Casie’s Flowers x Kelly’s Flowers
From whose garden will Casie choose “mates” for her flowers?
Codominance:
______________________________________________________________________________
_____________________________________________________________________________.
Example of Codominance:
______________________________________________________________________________
Practice Problems:
The gene for the coat color of shorthorn cattle in inherited by codominance. Red Shorthorn cattle
have RR genes. White shorthorn cattle have WW genes. Roan (coat of both red and white hairs)
cattle have RW genes.
1. Determine the genes of the offspring if a red cow and a roan bull are bred. Show a punnett
square. What % of offspring should have red coats? white coats? roan coats?
% red coats: __________
% white coats: _________
% roan coats: __________
2. Determine the offspring of two roan parents. Show a punnett square. What percentage of
offspring should have red coats? white coats? roan coats?
% red coat: ________
% white coat: ______
% roan coat: _______
3. In chickens, the allele for black feathers (B) is co-dominant with the allele for white feathers
(W). Heterozygous chickens appear speckled with black and white feathers.
A black chicken breeds with a heterozygous speckled chicken. What are the genotypic and
phenotypic ratios? Show a punnett square.
Genotypic Ratio: ________________________
Phenotypic Ratio: _______________________
4. A rooster and chicken mate. When the chicks hatch 3 are speckled, 2 are black and 1 is white.
What are the parents’s genotypes? Draw a punnett square to show your work.
Parent’s Genotypes: ____________ and _____________
Practice: Codominance and Incomplete Dominance
Name: ______________________
Mods: ____________
Directions: Look at the following examples. State whether each of the following is an example of
Co-dominance or Incomplete dominance. Then create genotypes based off of the given
phenotypes. Remember that the “medium” trait must always be heterozygous. An example has
been done for you.
Example: Black, grey, or white.
This is incomplete dominance because neither trait is being fully expressed, it’s a blend.
Genotypes: B1B1 – Black
B2B2 – Grey
B2B2 – White
a. Birds can be blue, white, or white with blue-tipped feathers.
b. Flowers can be white, pink, or red.
c. A Hoo can have curly hair, spiked hair, or a mix of both curly and spiked.
d. A Sneech can be tall, medium, or short.
e. A dog can be spotted, black, or white.
f. I ate a chocolate chip cookie, an Oreo cookie, and a chocolate chip Oreo cookie for lunch.
g. There were three types of flowers: green, blue, and yellow.
h. I raise cows, obviously, I have a black angus and a shorthorn cow. I cross these two cows and
get a ½ angus, ½ shorthorn.
1. In smileys, eye shape can be starred, circular, or a circle with a star. Write the genotypes for
the pictured phenotypes.
_____________
_____________
_____________
2. Is this an example of incomplete dominance or a co-dominance inheritance pattern?
________________________________________
3. Show the cross between a star-eyed and a circle-eyed.
4. What are the phenotypes of the offspring? ________________________
5. What are the genotypes? __________________________
6. Show the cross between a circle-star eyed, and a circle eyed.
7. What percent of the offspring have circle-eyes? ________________
8. What percent of the offspring have circle-star eyes? ________________
9. Show the cross between two circle-star eyed.
10. What percent of the offspring are circle-eyed? ______________
11. What percent of the offspring will have circle-star eyes? ______________
12. What is the possibility or chance of having a star-eyed child? _____________
13. Complete the punnet square for a cross between a homozygous red-flowered snapdragon
(R1R1) and a homozygous white-flowered snapdragon (R2R2). Give the genotype(s) and
phenotype(s) of the offspring in the F1 generation.
Genotype(s): __________________________
Phenotype(s): _________________________
14. When traits are inherited in an incomplete dominance pattern, what is true of the phenotype of
the heterozygotes?
_________________________________________________________________
15. Complete the punnett square for a cross between two pink-flowered F1 plants. Give the
phenotype ratio of the offspring in the F2 generation.
Phenotype ratio: _____________________
16. In what type of inheritance are both alleles expressed equally? ________________________
17. Complete the Punnett square for a cross between a black chicken (BB) and a white chicken
(WW). Give the phenotype of the offspring in the F1 generation.
Key__
BB - Black
WW – white
BW - checkered
Phenotype of offspring: _______________________________
18. What type of inheritance pattern is this? __________________________________________
Multiple Alleles:
______________________________________________________________________________
Example(s) of Multiple Alleles:
______________________________________________________________________________
Note: Even though there are multiple alleles for certain traits an individual can only carry _____
alleles because ______________________________________________________________.
Blood Types are also an example of multiple alleles.
How many different types of blood are there? ________________
What are the four blood types? ______________________________________
How many alleles control the blood types? ________________
Blood Types A and B are _________________________.
Blood Type O is _________________________.
Why is it important for you to know your blood type? ____________________________________
______________________________________________________________________________
______________________________________________________________________________
The blood type that is known as the Universal acceptor is ___________.
Universal acceptor means that people with this blood type can receive blood from anyone,
It doesn’t matter what their blood type is.
The blood type that is known as the Universal donor is ___________.
Universal donor means that their blood can be given to any individual regardless of their
blood type.
Practice Problems:
Your blood type is controlled by multiple alleles. Blood type is controlled by three alleles in which
A (IA) and B (IB) are codominant, and both are dominant over O (ii).
Type A Blood = IAIA or IAi
Type B Blood = IBIB or IBi
Type O Blood = ii
Type AB Blood = IAIB
1. If your mom has type AB blood and your dad has type O blood then what blood types could
your siblings have? Draw a punnett square to show the cross and possible offspring.
What are the possible blood types (phenotypes) of your siblings? __________________________
What are the possible genotypes from these two parents? _______________________________
2. A man with blood type B marries a woman with blood type A. They have four children, one with
the blood type AB, one with blood type A, one with the blood type B and one with the blood type
O. Draw a punnett square showing the cross. What are the genotypes of each parent?
Genotypes of Parents: _______________ and ________________
The chart below lists the blood phenotypes of 8 individuals. Use the information in the chart to
solve the genetics problems that follow.
Females
Anne
Wendy
Susan
Patricia
Blood Type
Type O
Type B
Type AB
Type A
Males
Charlie
Scott
Larry
Keith
Blood Type
Type A
Type AB
Type O
Type B
3. Larry has a son with type B blood. Which of the females listed above could be this child’s
biological mother?
Biological mother could be: _______________________________________________________
4. Keith and Wendy have a 4 year old son with type O blood. How is this possible? Use a
punnett square as part of your answer.
______________________________________________________________________________
______________________________________________________________________________
Blood Type compatibility:
What is an antibody? How do they relate to blood types?
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Can differences between a mother and fetus’s blood cause risks to the baby or mom? _________
Explain: _______________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Polygenetic Inheritance: ________________________________________________________
_____________________________________________________________________________
Example(s) of Polygenetic Inheritance: ____________________________________________
_____________________________________________________________________________
Most human traits are _____________________________.
Eye Color
-There are _________ known genes that control human eye color.
-Green alleles are ______________ to blue alleles
-Green alleles are _____________ to brown alleles
This does not account for all eye colors, like ____________, ________________, or eye color
that changes overtime or patterns in eye color.
Scientist hypothesize that we have not ______________ all the ______ that control eye color.
Epistasis
In mice, _____________ different genes affect __________________________.
Two genes give the mouse a __________________________.
One affects the ____________________.
One determines if it will have ____________________
The fifth determines if it will have _____________________________________.
________________________- gene that can interfere with the expression of other genes.
_______________- a lack of pigment in skin, hair and eyes.
A mouse that is__________________________ for the alleles that prevent
_________________________ of the skin will be white regardless of what those other genes
code for.
Environmental Influences
Effects of genes can be altered by the __________________________.
The genetic make-up of an organism at fertilization determines ___________________________
_____________________________________________________________________________
In what two ways can the environment affect the genetic make-up of an organism? ____________
______________________________________________________________________________
Examples of each: ________________________________________________________
________________________________________________________
Boy vs. Girl
All somatic, or regular chromosomes are identical pairs…Do sex chromosomes always match?
Why or why not? ________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Does the sperm or egg determine the sex of a baby? Why? ______________________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
X-Chromosome Inactivation
Since males have one ___ and one ___, they express all of the _______________ on both
chromosomes.
Even if males have all ___________________ genes, they will still be ___________________.
In females (_______) one of the _________________________ is turned off, this is
_________________________________.
Because one X-chromosome is randomly turned off, females are a ____________________ of
two types of cells. One type with an active X-chromosome from ___________ and one with an
active X-chromosome from __________.
Examples: ____________________________________________________________
Female calico cats have white fur and alleles for black and orange fur that are expressed
randomly in some cells.
Since males have only 1 X chromosome they can have black or orange.
Sex-Linked Traits:
______________________________________________________________________________
_____________________________________________________________________________.
What is the fate of a male who inherits an x-linked trait? Why? ___________________________
______________________________________________________________________________
______________________________________________________________________________
Will a female who inherits an x-linked trait have the same fate? Why or why not? _____________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Example of Sex-Linked Traits:
______________________________________________________________________________
Carrier: _______________________________________________________________________
Can sex-linked traits be hidden? __________
Explain: _______________________________________________________________________
Practice Problems:
The human blood clotting disorder is a recessive trait (must receive both recessive alleles to
express trait) which is found on the X chromosome.
XHXH and XHXh = females without hemophilia
XhXh = female with hemophilia
XHY = male without hemophilia
XhY = male with hemophilia
1. A woman who is heterozygous for hemophilia mates with a male without hemophilia. What
percent of the female offspring will be a carrier for hemophilia (heterozygous)? Describe the
phenotypes of the boy offspring.
Percent of female offspring that are carriers: _________________
Male offspring’s phenotypes: ______________________________________________________
2. A woman who is a carrier mates with a male with hemophilia.
Will any girls have hemophilia? ____________
Below is a chart listing some alien sex-linked characteristics. Use the chart to solve the genetics
problems below.
Trait
Chromosome
Dominant Phenotype
Body Color
Eye Color
Extra Arms
X
X
Y
Purple (P)
Yellow (E)
Extra arms present (4)
Recessive
Phenotype
Pink (p)
Red (e)
Extra arms present (4)
3. A male with yellow eyes mates with a red-eyed female. What is the chance that this couple will
have a baby boy with red eyes?
Probability of baby boy having red eyes: _______ %
4. A female, heterozygous for the body color trait mates with a pink male. What is the chance that
these aliens will give birth to a purple-skinned girls?
Purple-skinned Girl: _______ %
Genetic Disorder: ______________________________________________________________
______________________________________________________________________________
Mutation: _____________________________________________________________________
______________________________________________________________________________
What is the difference between a treatment and a cure? ________________________________
______________________________________________________________________________
______________________________________________________________________________
Cystic Fibrous
What is it?
What are the symptoms?
What is the ‘treatment’
Dominant or Recessive or Sex-linked
Other Important Information:
Sickle Cell Anemia
What is it?
What are the symptoms?
What is the ‘treatment’
Dominant or Recessive or Sex-linked
Other Important Information:
Hemophilia
What is it?
What are the symptoms?
What is the ‘treatment’
Dominant or Recessive or Sex-linked
Other Important Information:
Huntington’s
What is it?
What are the symptoms?
What is the ‘treatment’
Dominant or Recessive or Sex-linked
Other Important Information:
Down Syndrome
What is it?
What are the symptoms?
What is the ‘treatment’
Dominant or Recessive or Sex-linked
Other Important Information:
Diagnosing Genetic Disorders
What two things did Doctors rely on in the past in order to determine genetic disorders?
___________________________ and _______________________________
What two things do Doctors rely on today in order to determine genetic disorders?
____________________________ and _______________________________
How does the process of amniocentesis lead to a karyotype? _____________________________
______________________________________________________________________________
______________________________________________________________________________
Karyotype: ___________________________________________________________________
Karyotypes are arranged in pairs by ___________________ and __________________ of
centromeres.
Genetic Counseling
What does a genetic counselor do? Who might visit a Genetic counselor? ___________________
______________________________________________________________________________
______________________________________________________________________________
______________________________________________________________________________
Pedigree:
It is an important tool that geneticists use to ___________________________________________
______________________________________________________________________________
A pedigree is a chart or “ ______________________” that _______________________________
______________________________________________________________________________
Common Symbols Used In Pedigrees
Male
Female
Marriage (Husband and Wife)
Parents to their children
Siblings (Brothers and Sisters)
Individual is affected by trait (shows up)
Carrier of the trait
Death
Successive Generations are labeled by…
Individuals are labeled by…