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Study Guide — Unit 2 Chapter 5
DRAFT
Unit 2
Genetic Processes
Chapter 4 Heredity and Reproduction
BIG IDEAS
• Genetic and genomic research can have social
and environmental implications.
• Variability and diversity of organisms result from
the distribution of genetic materials during the
process of meiosis.
Genetic information is passed from one generation to the next in the process of
reproduction. This genetic information is stored in DNA molecules which are
organized into genes on chromosomes.
There are two types of reproduction. Asexual reproduction involves one
parent; it produces offspring that are genetically identical to the parent. Sexual
reproduction involves two parents; it produces genetically variable offspring. Each
of these processes has biological advantages and disadvantages.
Information about sexual and asexual reproduction, and how genetic
information is transmitted during these processes, has applications related to
human health, to agriculture, and to the environment.
Chapter 5 Mendelian Genetics—Patterns of
Inheritance
Our understanding of how traits are transmitted during reproduction is due largely
to the work of Gregor Mendel, the “Father of Genetics.” He used the results of
many experiments to develop laws describing the inheritance of traits.
There are many patterns of inheritance beyond those studied by Mendel.
Patterns of inheritance include complete dominance, incomplete dominance, and
codominance. Some traits, such as human skin colour, are controlled by multiple
pairs of alleles, resulting in a great amount of variation. Genetic factors play a role
in many disorders, such as cystic fibrosis. Genetic screening and carrier testing can
help determine the risk of expressing or passing on a genetic disorder. There are
social and ethical implications associated with genetic screening and carrier testing.
Chapter 6 Genetics Beyond Mendel
Genetic information is stored in DNA molecules. DNA is a double helix consisting
of pentose sugars, phosphate groups, and nitrogenous bases. Mutations, which are
changes in the sequence of nitrogenous bases in DNA, can occur due to
environmental factors or errors in replication.
Genomes of different organisms contain different numbers of genes. The
human genome, which consists of about 20 000 genes, has been sequenced, and this
information can be used in medical and forensic applications.
Genetic engineering uses a variety of techniques to manipulate genetic
information. Gene therapy applies genetic engineering to overcome the effects of
defective genes. Genetic engineering and gene therapy have social and
environmental considerations. Manipulation of the genome has environmental and
social consequences.
Copyright 2011 by Nelson Education Ltd.
DRAFT
Unit 2 Overview 1
5.1
Textbook pp. 184–193
LEARNING TIP
Characteristic or Trait
Do not confuse the terms “characteristic” and
“trait.” Traits represent the variation within a
characteristic. For example, height is a
characteristic, while short and tall are traits; sight
is a characteristic, while normal vision, nearsightedness, and far-sightedness are traits.
Mendelian Inheritance
Vocabulary
trait
true-breeding organism
hybrid
cross
P generation
F1 generation
monohybrid
monohybrid cross
F2 generation
law of segregation
allele
homozygous
heterozygous
genotype
phenotype
dominant allele
recessive allele
Punnett square
probability
test cross
Main idea: Gregor Mendel was the first person to record and quantify the inheritance of traits
in an organism over many generations. He did this through the selective cross-breeding of
common pea plants (Pisum sativum). His experiments laid the groundwork for modern day
genetics.
1.
Why did Mendel select the pea plant for his experiments? Give three
characteristics of the pea plant that make it ideal for crosses.
2.
Explain the significance of Mendel’s use of true-breeding plants in his
experiments.
3.
Explain how the characteristics that Mendel chose to study aided his study on
the inheritance of traits.
4.
Define “monohybrid cross” and explain its significance in experiments that
study the inheritance of traits.
Copyright 2011 by Nelson Education Ltd.
DRAFT
Unit 2 Ch 5 1
Main idea: Mendel’s data revealed patterns of inheritance.
Table 1 Mendel’s Data
Characteristics
seed shape
P
round × wrinkled
F1
all round
seed color
yellow × green
all yellow
pod shape
all inflated
pod colour
inflated ×
constricted
green × yellow
flower colour
purple × white
all purple
flower position
axial × terminal
all axial
stem length
tall ×
dwarf
all tall
5.
all green
F2
5474 round
1850 wrinkled
6022 yellow
2001 green
882 inflated
299 constricted
428 green
152 yellow
705 purple
224 white
651 axial
207 terminal
787 tall
277 dwarf
Ratio
2.96 : 1
3.01 : 1
2.95 : 1
2.82 : 1
3.15 : 1
3.14 : 1
2.84 : 1
(a) Write a sentence that summarizes the mathematical pattern in Mendel’s
data for the F1 generation (Table 1).
(b) Write a sentence that summarizes the mathematical pattern in Mendel’s
data for the F2 generation (Table 1). [T/I] [C]
6.
(a) What were Mendel’s two main conclusions about how traits are passed
from one generation to the next?
(b) What is the formal name used to describe Mendel’s two conclusions?
[K/U] ______________________________
Main idea: Genes have alternate forms called alleles.
LEARNING TIP
Dominance
In genetics, dominance refers only to which gene
is expressed in an organism. It does not mean that
the allele is stronger, better, or more common
than the recessive allele.
7.
A(n) ___________ is any of the alternate forms of a gene that may occur at a
specific locus.
8.
Cells have two alleles for each gene, one from each parent. If the two alleles for
a particular gene are the same, the individual is ___________ for that allele. If
the two alleles for a particular gene are different, the individual is __________
for that allele. [K/U]
Main idea: Genes influence traits.
9.
The set of alleles an individual has, or its genetic makeup, is known as its
_____________. [K/U]
10. An individual’s outward appearance with respect to a specific characteristic is
its ____________. [K/U]
11. Some alleles are dominant, while others are recessive. __________ alleles are
always expressed in the phenotype, whereas __________ alleles do not show
up unless they are the only allele present the genotype. [K/U]
Copyright 2011 by Nelson Education Ltd.
DRAFT
Unit 2 Ch 5 2
Use Figure 1 to answer questions 12 and 13.
Figure 1
12. Based on the information in Figure 1, which allele for plant height is
dominant? [T/I] _________
13. Circle any plant or plants shown in Figure 1 that are homozygous. Cross out
any plant or plants that are heterozygous. [K/U]
14. Explain how two different genotypes may result in the same phenotype. [K/U]
Main idea: A Punnett square is a diagram used to predict the proportions of genotypes in the
offspring resulting from a cross between two individuals.
15. (a) What does the information on each axis of a Punnett square represent?
(b) What does the information inside a Punnett square represent? [K/U]
STUDY TIP
16. In pea plants, the trait of axial flowers, A, is dominant, and the trait of terminal
flowers, a, is recessive. Draw a Punnett square in the space below that shows a
cross between two pea plants heterozygous for the trait of flower position. The
genotype of each parent plant is Aa. [T/I][C]
A Punnett square can be used to predict the
inheritance of alleles. Use a Punnett square when
you are asked to find the possible genotypes of
offspring that result from a cross.
17. Explain how a test cross can be used to determine the genotype of an unknown
parent. [K/U]
Copyright 2011 by Nelson Education Ltd.
DRAFT
Unit 2 Ch 5 3
5.2
Variations in Heredity
Vocabulary
Textbook pp. 194–196
complete dominance
incomplete dominance
codominance
Main idea: Alleles that determine the phenotype regardless of the presence of other alleles
follow a pattern of inheritance called complete dominance.
1.
Mendel’s experiments involved crossing homozygous dominant plants with
homozygous recessive plants. In these crosses, only one allele is expressed in
the phenotype despite the presence of the other allele. This pattern of
inheritance called __________ __________. [K/U]
2.
Use your knowledge of complete dominance to explain why individuals who
are heterozygous and those that are homozygous for the dominant allele can
have different genotypes but the same phenotype. [T/I][A]
LEARNING TIP
Notation of Alleles
Notation of alleles for a specific gene can be
represented using superscripts. For example,
consider the alleles for colour in snapdragons. The
gene is C for colour. The alleles are red (R) and
white (W). When you combine the notations for
genes and alleles, the result is CR for the red allele
and CW for the white allele.
LEARNING TIP
Notation of Alleles in Incomplete
Dominance
In incomplete dominance, alleles are neither
dominant nor recessive. In this situation,
uppercase letters with superscripts are used to
represent different alleles.
Main idea: Not all traits are inherited in simple patterns such as complete dominance.
Variations in the patterns of heredity exist, and dominance is not always complete.
3.
____________ ____________ occurs when neither allele dominates the other
and both exercise an influence on the phenotype, resulting in partial
expression of both traits. [K/U]
4.
The snapdragon is an organism that displays incomplete dominance for flower
colour. Complete Table 1 by recording the flower colour, or phenotype,
associated with each genotype. [K/U]
Table 1 Snapdragon Genotypes and Phenotypes
Genotype
Phenotype
CRCR
CRCW
CWCW
5.
(a) Draw a Punnett square to show a cross between two pink-flowered
snapdragons.
(b) What percentage of the offspring will have pink flowers? _______[T/I]
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DRAFT
Unit 2 Ch 5 4
6.
(a) Draw a Punnett square to show a cross between a red snapdragon and a
white snapdragon.
(b)What percentage of the offspring will have pink flowers? _______ [T/I]
Main idea: Codominance occurs when both alleles are fully expressed, producing offspring
with a third genotype.
7.
Type AB blood is an example of codominance. Draw a Punnett square to show
a cross between an individual with type A blood (genotype IAi) and an
individual with type B blood (genotype IBi). Circle any offspring that will have
type AB blood. [T/I][A]
Main idea: Blood type is an example of a gene with multiple alleles. The three blood types
alleles are IA, IB, and i. Different combinations of the three alleles produce type A, type B, type
AB, and type O blood.
8.
STUDY TIP
Charts and Tables
Charts and tables are an effective way to organize
information. Create a graphic organizer to
differentiate between complete dominance,
incomplete dominance, and codominance.
(a) Fill in the missing information in the Table 2 below to reinforce what you
know about human blood types. [T/I]
Table 2 Human Blood Types
Genotype
Blood Type
IAIA
A
A
Ii
Able to receive
blood from
Able to donate
blood to
A, AB
A
IBIB
IBi
IAIB
B
AB
ii
(b) Which blood type is known as the universal donor? Why?
(c) Which blood type is known as the universal recipient? Why? [K/U][T/I]
Copyright 2011 by Nelson Education Ltd.
DRAFT
Unit 2 Ch 5 5
5.3
Pedigrees−Tracking Inheritance
Vocabulary
pedigree
autosomal inheritance
Textbook pp. 197–201
sex-linked
X-linked
Y-linked
Main idea: A pedigree chart traces the inheritance of a trait among members of a family.
It shows the connections between parents and offspring, the sex of individuals in each generation,
and the presence or absence of a trait.
1.
STUDY TIP
Pedigree Chart Symbols
You can use a pedigree chart to track the
inheritance of traits through generations of a
family. With a partner, use flashcards to review the
symbols used on pedigree charts.
Use the terms in the box below to label the pedigree symbols below. [K/U]
affected female
affected male
fraternal twins
identical twins
normal female
normal male
mating
siblings
(a) ________
(c) ________
(e) ________
(g) _______
(b) ________
(d) ________
(f) ________
(h) ________
2.
Draw a pedigree chart for the following: A man and a woman are both
heterozygous for a recessive genetic disorder. They have three children: an
unaffected female, an unaffected male, and an affected female. The affected female
and a man who is heterozygous for the disorder have male fraternal twins who are
both affected. [T/I] [A]
3.
Describe how phenotypes can be used to predict genotypes in a pedigree.
Copyright 2011 by Nelson Education Ltd.
DRAFT
Unit 2 Ch 5 6
Main idea: The expression of genes on the sex chromosomes differs from the expression of
autosomal genes.
4.
If an allele is located on an autosome, or a non-sex chromosome, it is transmitted
through __________ inheritance. [K/U]
5.
In autosomal inheritance, males and females are affected at _______ rates. [K/U]
6.
Identify the two human chromosomes on which an autosomal allele could not be
located. [K/U]
7.
Sex-linked inheritance occurs when a ________ allele on the X or Y chromosome
of the parent is passed on to the offspring. [K/U]
8.
Red-green colour blindness is an example of X-linked inheritance. A woman who
is an unaffected carrier of red-green colour blindness and a man who has normal
vision are expecting a child. Draw a Punnett square to show the possible genotypes
of their offspring. Use XR to represent the normal allele and Xr to represent the
allele for red-green colour blindness. [T/I]
9.
Use the information in the completed Punnett square from question 8 to answer
the following questions. [T/I] [A]
(a) What percentage of the male offspring would you expect to have red-green
colour blindness? _______
(b) What percentage of female offspring would you expect to be unaffected carriers
of red-green colour blindness? ________
(c) How does the expression of the red-green colour blindness trait differ between
male offspring and female offspring?
10. Can a male be an unaffected carrier of a recessive X-linked trait? Explain. [T/I] [A]
Copyright 2011 by Nelson Education Ltd.
DRAFT
Unit 2 Ch 5 7
5.4
Textbook pp. 202–203
Biology Journal: The Gene Hunters
Main idea: The gene for Huntington’s disease has been located through extensive research.
Research continues as scientists seek a way to prevent or cure this disease.
1.
Use the mind map below to take notes about Huntington’s disease and the
search for the Huntington’s disease gene. [K/U][C]
Symptoms:
Tools and Techniques Used in
Research:
Huntington’s
disease
STUDY TIP
Mind Maps
You can use a mind map to organize information
found in a reading passage.. In this case, the mind
map helps collect and organize the main ideas
found throughout the reading selection.
Mode of Inheritance:
Location of Marker:
2.
People from all walks of life can make contributions to science. Explain why
the hunt for the gene that causes Huntington’s disease is an example of this
fact. [T/I] [A]
3.
Scientific inquiry involves questioning, researching, identifying and
controlling variables, hypothesizing, predicting, planning, performing and
recording, observing, analyzing, evaluating, and communicating. How did
Dr. Nancy Wexler’s work fit this pattern? Use examples to justify your answer.
[T/I][A]
Copyright 2011 by Nelson Education Ltd.
DRAFT
Unit 2 Ch 5 8
5.5
Textbook pp. 204–207
Genetic Disorders
Vocabulary
mutation
carrier testing
genetic screening
phenylketonuria (PKU)
Main idea: Many human disorders have a genetic component.
1.
A change in the genetic code of an allele is called a ___________.
2.
Which of the following disorders is not caused by a gene mutation?
(a) Huntington’s disease
(b) Phenylketonuria
(c) asthma
(d) hemophilia
3.
Indicate whether the following statement is true or false. If you think the
statement is false, rewrite it to make it true: Cystic fibrosis is the passed on
through a dominant mutated gene.
4.
Complete the Punnett square below to show the possible offspring of an
unaffected male carrier of cystic fibrosis and a female with two normal alleles.
Use F for the normal allele and f for the cystic fibrosis allele. [T/I] [A]
STUDY TIP
Punnett Squares
You can use a Punnett square to predict the
proportions of genotypes in the offspring resulting
from a cross between two individuals. Practise
using a Punnett square for various crosses,
including the one shown in question 4.
(a) What percentage of the possible offspring does not carry an allele for cystic
fibrosis? _______
(b) What percentage of the possible offspring are unaffected carriers of a cystic
fibrosis allele? _______
(c) What percentage of the possible offspring will have cystic fibrosis? _______
5.
Copyright 2011 by Nelson Education Ltd.
Would your answers to question 4 differ if it was the female was a healthy
carrier of the cystic fibrosis allele and the male had two normal alleles?
Explain your response. [T/I] [A]
DRAFT
Unit 2 Ch 5 9
Main idea: Genetic screening is used to detect mutated genes that cause genetic disorders.
6.
Genetic screening is used to identify the presence of a defective allele that leads
to a genetic disorder. Explain how a genetic counsellor might use a pedigree
chart in addition to DNA testing in order to diagnose a genetic disorder. [T/I]
7.
Explain how genetic screening can be used to predict the severity of cystic
fibrosis symptoms an affected individual will have. [T/I]
8.
Explain how a mutation in BRCA1 or BRCA2 can lead to the development of
cancer. [T/I] [A]
Main idea: Newborn genetic screening is now used to identify the presence or absence of
defective genes in many countries, including in Canada.
10. List three specific disorders that are part of Ontario’s newborn screening
program. [K/U]
Copyright 2011 by Nelson Education Ltd.
DRAFT
Unit 2 Ch 5 10
5.6
Textbook pp.208–209
Explore an Issue in Genetic Screening
Main idea: Genetic testing has many benefits, but the use and ownership of the results has
raised many ethical and legal issues.
1.
Legal access to and ownership of genetic information are topics that will
become increasingly important as the ability to test for specific genes and
disorders increases. In the chart below, add facts and opinions related to each
of the listed questions. When you have completed the chart, you can review the
information you have recorded to help you form guidelines about these
important issues. [C] [A]
Question
STUDY TIP
Organizing Facts and Opinions for Discussion
Charts can be used to organize information related
to complex issues. In this chart, you should record
your thoughts and opinions about each of the
questions listed. Then, you can use this
information in group discussions.
Facts and Opinions
Who makes decisions about
access to genetic
information?
LEARNING TIP
Making Decisions as a Group
Before you come to a decision as a group, make a
list on chart paper of pros and cons for the
question at hand. Place the chart paper where all
group members can see and have access to it.
This can be helpful in forming new thoughts and
ideas about the discussion at hand. During a
brainstorming session like this one, take an
accepting attitude of all the ideas presented to the
group. Wait until the page is full to critique the
ideas.
Who should have access to
an individual’s genetic
information?
Should an individual ever be
required by law to share
genetic information?
Copyright 2011 by Nelson Education Ltd.
DRAFT
Unit 2 Ch 5 11
5.7
Textbook pp. 210–214
Multi-trait Inheritance
Vocabulary
dihybrid cross
law of independent assortment
product law
discontinuous variation
continuous variation
additive allele
Main idea: A dihybrid cross involves two traits.
1.
A dihybrid cross involves a cross between two individuals who differ in two
pairs of __________.
2.
Mendel performed dihybrid crosses in plants that were true-breeding for two
traits. For example, a plant that had yellow seed colour and round seed shape
was crossed with a plant that had green seed colour and wrinkled pod shape.
In this cross, the traits for yellow seed colour (YY) and round pod shape (RR)
are dominant. Green seed colour (yy) and wrinkled pod shape (rr) are
recessive. [T/I] [C]
(a) Draw a Punnett square to show the genotypes of the resulting offspring.
LEARNING TIP
Gene Order
When completing the Punnett square for a
dihybrid cross, keep the genes in alphabetical
order and write the dominant alleles (capital
letters) first, for example, TtPp.
(b) If the F1 generation was then crossed, what would be the resulting genotype
ratio of the F2 generation?
3.
Copyright 2011 by Nelson Education Ltd.
Mendel crossed numerous heterozygous F1 generation plants. What did his
experiments reveal to him about the inheritance of traits? Explain your
reasoning. [T/I]
DRAFT
Unit 2 Ch 5 12
Main idea: Mendel’s law of independent assortment states that alleles of different genes
separate into gametes independently of one another.
4.
In pea plants, the allele for the trait of tall plants (T) is dominant; the allele for
dwarf plants is recessive (t). The allele for purple flowers (P) is dominant; the
allele for white flowers (p) is recessive. Complete the Punnett square below
(Figure 1) to show the dihybrid cross between two pea plants, both of which
are heterozygous for these traits. [T/I]
TP
STUDY TIP
TP
Developing Explanations
Diagrams can be used to visualize concepts and
ideas. In this case, a Punnett square is used to
show how alleles assort independently. Using your
completed diagram, explain this concept to a
friend.
Tp
Tp
tP
tp
tP
tp
Figure 1
5.
LEARNING TIP
Fill in Table 1 below to show the ratio of the phenotypes of the offspring in the
dihybrid cross in question 4. [A]
Table 1 Phenotypic Ratios
Sample Size
Note that Mendel observed these ratios only
because of his large sample size. He crossed
hundreds of plants, producing thousands of
offspring. As sample size increases, the closer the
experimental (actual probability gets to theoretical
probability.
Number of
offspring
(a)
Phenotype
9
(b)
tall plants, white flowers
(c)
3
(d)
6.
An individual is heterozygous for two traits. His genotype for those traits is
BbGg. In Figure 2 below, show the four possible gametes this individual can
produce. [T/I] [A]
BbGg
_____
_____
_____
_____
Figure 2
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DRAFT
Unit 2 Ch 5 13
Main idea: Genetic ratios are probabilities.
7.
The probability of two independent events both occurring may be calculated
using the _________ __________.
8.
To calculate the probability of two independent events both occurring,
multiply their individual _______________.
9.
In a dihybrid cross, either a Punnett square or the probability law can be used
to determine the likelihood of a particular outcome. Compare the predicted
probabilities using each of these methods compare. [T/I]
Main idea: Variation in the expression of genes can be described as either continuous or
discontinuous.
10. ______________ variation occurs when a trait is either expressed or is not (i.e.
there is no in-between trait). _____________ variation occurs in nature when
the expression of a characteristic is a sum of the expression of all alleles
involved. [K/U]
11. Classify the pea plant traits studied by Mendel as continuous or discontinuous.
Write a sentence to justify your classification. [T/I]
12. Identify a human trait that exhibits continuous variation. [K/U]
13. Define the term “additive allele.” [K/U]
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DRAFT
Unit 2 Ch 5 14
Chapter 5 Summary
Mendelian Genetics—Patterns of Inheritance
Gregor Mendel
is known as the “Father of Genetics” because of his study of the inheritance of certain traits in pea plants.
Mendel showed that the inheritance of these traits follows particular laws.
law of segregation
law of independent assortment
based on the conclusions that
which states
for each
characteristic, an
organism carries
two genes: one
from each parent.
if genes are located on
separate chromosomes,
they will be inherited
independently of one
another.
parent organisms donate only
one copy of each gene in their
gametes. During meiosis, the
two copies of each gene
separate, or segregate.
Patterns of inheritance
can be tracked and
predicted using tools
such as
Punnett squares
include
pedigree charts
complete
dominance
which occurs when
one allele
determines the
phenotype,
regardless of the
presence of
another allele
incomplete
dominance
which occurs when
neither allele dominates
the other; both exercise
an influence on the
individual, resulting in
partial expression of both
traits
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DRAFT
codominance
which occurs when
both alleles are
expressed fully,
resulting in
offspring with a
third phenotype
Unit 2 Ch 5 15
Chapter 5 Questions
K/U
T/I
C
A
Knowledge/Understanding
Thinking/Investigation
Communication
Application
For each question, select the best answer from the four alternatives.
1.
Which of the following statements is one of the conclusions that forms the law of segregation? (5.1) [K/U] U
(a) Each parent passes on only one of its two alleles for each gene.
(b) Dominant alleles, if present, are always passed on.
(c) The frequency of genotypes among offspring is random and cannot be predicted.
(d) Individuals have a single, segregated allele for each gene.
2.
An individual with the genotype IAi has type A blood. What do this particular genotype and phenotype demonstrate?
(5.2) [K/U]
(a) compatible dominance
(b) codominance
(c) complete dominance
(d) incomplete dominance
Indicate whether each of the statements is true or false. If you think the statement is false, rewrite it
to make it true.
3. A diagram used to show the inheritance of a trait through generations of a family is called a
Punnett square. (5.3) [K/U]
4.
Nancy Wexler is a scientist who investigated the cause of phenylketonuria. (5.4) [K/U]
Respond to each statement or answer each question below.
5. An individual with type AB blood marries an individual with type O blood. Is it possible for their
offspring to have the same blood type as either parent? Explain your response. (5.2) [T/I] [A]
6.
Describe the symptoms of cystic fibrosis. Then, classify the allele that causes the disorder as
dominant or recessive and state whether it is autosomal or X-linked. (5.5) [K/U][T/I]
7.
Identify one ethical issue related to genetic screening. Then, write a sentence that summarizes
your opinion on this issue. (5.6) [T/I] [A]
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DRAFT
Unit 2 Ch 5 16
8.
Compare and contrast discontinuous and continuous variation. Identify one way they are similar
and one way they are different. (5.7) [T/I]
9.
In humans, the allele M codes for melanin, the allele m does not. Individuals with the genotype
mm have albinism. Draw a Punnett square to show a cross between two individuals who are
heterozygous for this trait and circle any possible offspring who will have albinism. (5.1) [T/I] [C]
10. Fill in Table 1 below to compare codominance, complete dominance, and incomplete
dominance. (5.2) [T/I] C]
Table 1
Codominance
Complete dominance
Incomplete dominance
Number of alleles
present
Number of alleles that
affect phenotype
Phenotype of
heterozygote
11. Draw a pedigree chart to show the following: A man with an autosomal recessive disorder and a
woman who does not carry the allele for this disorder have three children: a son, a daughter, and
another son. None of the children have the disorder. The youngest son and a woman who is an
unaffected carrier of this disorder have two daughters. Both of their daughters have the disorder.
(5.3) [T/I] [C] [A]
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DRAFT
Unit 2 Ch 5 17