Chapter 11 Complex Inheritance and
Human Heredity
Section 1: Basic Patterns of Human Inheritance
Section 2: Complex Patterns of Inheritance
Section 3: Chromosomes and Human Heredity
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Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Recessive Genetic Disorders
 A recessive
trait is
expressed
when the
individual is
homozygous
recessive for
the trait.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Cystic Fibrosis
 Affects the mucus-producing glands,
digestive enzymes, and sweat glands
 Chloride ions are not absorbed into the
cells of a person with cystic fibrosis but
are excreted in the sweat.
 Without sufficient chloride ions in the cells,
a thick mucus is secreted.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Albinism
 Caused by altered genes, resulting in the
absence of the skin pigment melanin in hair
and eyes
 White hair
 Very pale skin
 Pink pupils
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Tay-Sachs Disease
 Caused by the absence of the enzymes
responsible for breaking down fatty acids
called gangliosides
 Gangliosides accumulate in the brain,
inflating brain nerve cells and causing
mental deterioration.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Galactosemia
 Recessive genetic disorder characterized by
the inability of the body to digest galactose.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Dominant Genetic Disorders
 Huntington’s disease affects the nervous
system.
 Achondroplasia is a genetic condition that
causes small body size and limbs that are
comparatively short.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Chapter 11
Complex Inheritance and Human Heredity
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Pedigrees
 A diagram that traces the inheritance of a
particular trait through several generations
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Inferring Genotypes
 Knowing physical traits can determine what
genes an individual is most likely to have.
Predicting Disorders
 Record keeping helps scientists use
pedigree analysis to study inheritance
patterns, determine phenotypes, and
ascertain genotypes.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Incomplete Dominance
 The heterozygous phenotype is an
intermediate phenotype between the two
homozygous phenotypes.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Codominance
 Both alleles are expressed in the
heterozygous condition.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Sickle-cell Disease
Normal red blood cell
 Changes in hemoglobin
cause red blood cells to
change to a sickle shape.
 People who are
heterozygous for the trait
have both normal and
sickle-shaped cells.
Sickle cell
7766x
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Multiple Alleles
 Blood groups in
humans
 ABO blood groups
have three forms
of alleles.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Coat Color of Rabbits
 Multiple alleles can demonstrate a hierarchy
of dominance.
 In rabbits, four alleles code for coat color:
C, cch, ch, and c.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Coat Color of Rabbits
Chinchilla
Albino
Light gray
Dark gray
Himalayan
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Epistasis
 Variety is the result of one allele hiding the
effects of another allele.
eebb
eeB_
No dark pigment present in fur
E_bb
E_B_
Dark pigment present in fur
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Sex Determination
 Sex chromosomes
determine an
individual’s gender.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Dosage Compensation
 The X chromosome carries a variety of
genes that are necessary for the
development of both females and males.
 The Y chromosome mainly has genes that
relate to the development of male
characteristics.
 Chromosome inactivation
 Barr bodies
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Sex-Linked Traits
 Genes located on the X chromosome
 Red-green color blindness
 Hemophilia
Sex-Linked
Traits
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Polygenic Traits
 Polygenic traits arise from the interaction of
multiple pairs of genes.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Environmental Influences
 Environmental factors
 Diet and exercise
 Sunlight and water
 Temperature
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Twin Studies
 Helps scientists separate genetic contributions
from environmental contributions
 Traits that appear frequently in identical twins
are at least partially controlled by heredity.
 Traits expressed differently in identical twins
are strongly influenced by environment.
Chapter 11
Complex Inheritance and Human Heredity
11.3 Chromosomes and Human Heredity
Karyotype Studies
 Karyotype—micrograph in which the pairs of
homologous chromosomes are arranged in
decreasing size.
 Images of chromosomes stained during
metaphase
 Chromosomes are arranged in decreasing
size to produce a micrograph.
Chapter 11
Complex Inheritance and Human Heredity
11.3 Chromosomes and Human Heredity
Telomeres
 Telomere caps consist of DNA associated
with proteins.
 Serves a protective function for the structure
of the chromosome
Chapter 11
Complex Inheritance and Human Heredity
11.3 Chromosomes and Human Heredity
Nondisjunction
 Cell division during which sister chromatids
fail to separate properly
 Down syndrome
Visualizing
Nondisjunction
Chapter 11
Complex Inheritance and Human Heredity
Chapter 11
Complex Inheritance and Human Heredity
Chapter Resource Menu
Chapter Diagnostic Questions
Formative Test Questions
Chapter Assessment Questions
Standardized Test Practice
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Chapter 11
Complex Inheritance and Human Heredity
Chapter Diagnostic
Questions
Identify the disease characterized by the
absence of melanin.
A. albinism
B. cystic fibrosis
C. galactosemia
D. Tay-Sachs
Chapter 11
Complex Inheritance and Human Heredity
Chapter Diagnostic
Questions
An individual with Tay-Sachs disease would be
identified by which symptom?
A. excessive mucus production
B. an enlarged liver
C. a cherry-red spot on the back of the eye
D. vision problems
Chapter 11
Complex Inheritance and Human Heredity
Chapter Diagnostic
Questions
Under what circumstances will a recessive trait
be expressed?
A. A recessive allele is passed on by both
parents.
B. One parent passes on the recessive allele.
C. The individual is heterozygous for the trait.
D. There is a mutation in the dominant gene.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Formative
Questions
Which of Dr. Garrod’s observations about
alkaptonuria was most critical to his determination
that it is a genetic disorder?
A. It appears at birth and runs in families.
B. It is linked to an enzyme deficiency.
C. It continues throughout a patient’s life,
affecting bones and joints.
D. It is caused by acid excretion and results
in black urine.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Formative
Questions
Which is the genotype of a person who is
a carrier for a recessive genetic disorder?
A. DD
B. Dd
C. dd
D. dE
Chapter 11
Complex Inheritance and Human Heredity
11.1 Formative
Questions
Albinism is a recessive condition. If an albino
squirrel is born to parents that both have normal
fur color, what can you conclude about the
genotype of the parents?
A. at least one parent is a carrier
B. both parents are carriers
C. both parents are homozygous recessive
D. at least one parent is homozygous dominant
Chapter 11
Complex Inheritance and Human Heredity
11.2 Formative
Questions
When a homozygous male animal with black
fur is crossed with a homozygous female with
white fur, they have offspring with gray fur.
What type of inheritance does this represent?
A. dosage compensation
B. incomplete dominance
C. multiple alleles
D. sex-linked
Chapter 11
Complex Inheritance and Human Heredity
11.2 Formative
Questions
Of the 23 pairs of chromosomes in human
cells, one pair is the _______.
A. autosomes
B. Barr bodies
C. monosomes
D. sex chromosomes
Chapter 11
Complex Inheritance and Human Heredity
11.2 Formative
Questions
Which is an example of a polygenic trait?
A. blood type
B. color blindness
C. hemophilia
D. skin color
Chapter 11
Complex Inheritance and Human Heredity
11.3 Formative
Questions
What does a karyotype show?
A. The blood type of an individual.
B. The locations of genes on a chromosome.
C. The cell’s chromosomes arranged in order.
D. The phenotype of individuals in a pedigree.
Chapter 11
Complex Inheritance and Human Heredity
11.3 Formative
Questions
What is occurring in this
diagram?
A. multiple alleles
B. nondisjunction
C. nonsynapsis
D. trisomy
Chapter 11
Complex Inheritance and Human Heredity
11.3 Formative
Questions
What condition occurs when a person’s cells
have an extra copy of chromosome 21?
A. Down syndrome
B. Klinefelter’s syndrome
C. Tay-Sachs syndrome
D. Turner’s syndrome
Chapter 11
Complex Inheritance and Human Heredity
Chapter Assessment
Questions
Use the figure to describe what the top horizontal
line between numbers 1 and 2 indicates.
A. 1 and 2 are siblings
B. 1 and 2 are parents
C. 1 and 2 are offspring
D. 1 and 2 are carriers
Chapter 11
Complex Inheritance and Human Heredity
Chapter Assessment
Questions
Which is not an allele
in the ABO blood group?
A. IA
B. IO
C. IB
D. i
Chapter 11
Complex Inheritance and Human Heredity
Chapter Assessment
Questions
Down Syndrome results from what change in
chromosomes?
A. one less chromosome on pair 12
B. one extra chromosome on pair 21
C. one less chromosome on pair 21
D. one extra chromosome on pair 12
Chapter 11
Complex Inheritance and Human Heredity
Standardized Test
Practice
If a genetic disorder is caused by a dominant
allele, what is the genotype of those who do
not have the disorder?
A. heterozygous
B. homozygous dominant
C. homozygous recessive
Chapter 11
Complex Inheritance and Human Heredity
Standardized Test
Practice
Analyze this pedigree showing the inheritance of
a dominant genetic disorder. Which would be the
genotype of the first generation father?
A. RR
B. Rr
C. rr
Chapter 11
Complex Inheritance and Human Heredity
Standardized Test
Practice
Shorthorn cattle have an allele for both red and
white hair. When a red-haired cow is crossed with
a white-haired bull, their calf has both red and
white hairs scattered over its body. What type of
inheritance does this represent?
A. codominance
B. dosage compensation
C. epistasis
D. sex-linked
Chapter 11
Complex Inheritance and Human Heredity
Standardized Test
Practice
Why are males affected by recessive sexlinked traits more often than are females?
A. Males have only one X chromosome.
B. Males have two X chromosomes.
C. Males have only one Y chromosome.
D. The traits are located on the Y
chromosomes.
Chapter 11
Complex Inheritance and Human Heredity
Standardized Test
Practice
A carrier of hemophilia and her husband, who
is unaffected by the condition, are expecting a
son. What is the probability that their son will
have hemophilia?
A. 25%
B. 50%
C. 75%
D. 100%
Chapter 11
Complex Inheritance and Human Heredity
Glencoe Biology Transparencies
Chapter 11
Complex Inheritance and Human Heredity
Image Bank
Chapter 11
Complex Inheritance and Human Heredity
Vocabulary
Section 1
carrier
pedigree
Chapter 11
Complex Inheritance and Human Heredity
Vocabulary
Section 2
incomplete
dominance
codominance
multiple alleles
epistasis
sex chromosome
autosome
sex-linked trait
polygenic trait
Chapter 11
Complex Inheritance and Human Heredity
Vocabulary
Section 3
karyotype
telomere
nondisjunction
Chapter 11
Complex Inheritance and Human Heredity
Animation
 Visualizing Nondisjunction