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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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Section 1
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
I. Recessive Genetic Disorders (more common)
 A recessive
trait is
expressed
when the
individual is
homozygous
recessive for
the trait.
Section 1
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
A. Cystic Fibrosis (common in caucasians)
 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.
Section 1
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
B. 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
Section 1
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
C. Tay-Sachs Disease (common in Jewish)
 Death by age 5
 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.
Section 1
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
D. Galactosemia
 Recessive genetic disorder characterized by
the inability of the body to digest galactose
and glucose.
 Avoid milk products.
Section 1
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
II. Dominant Genetic Disorders
 Only need 1 dominant allele.
 A. Huntington’s disease affects the nervous
system. *Late onset!*
 B. Achondroplasia is a genetic condition that
causes small body size and limbs that are
comparatively short. (“Dwarfism”)
Section 1
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
Section 1
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
III. Pedigrees
 A diagram that traces the inheritance of a
particular trait through several generations
Section 1
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
A. Inferring Genotypes
 Knowing physical traits can determine what
genes an individual is most likely to have.
B. Predicting Disorders
 Record keeping helps scientists use
pedigree analysis to study inheritance
patterns, determine phenotypes, and
ascertain genotypes.
Chapter
Complex Inheritance and Human Heredity
Section 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.
1.
A
C. It continues throughout a patient’s life,2.affecting
B
bones and joints.
3.
C
4.
D. It is caused by acid excretion and results
inD black
urine.
Chapter
Complex Inheritance and Human Heredity
Section 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
1.
2.
3.
4.
A
B
C
D
Chapter
Complex Inheritance and Human Heredity
Section 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.
B.
C.
D.
at least one parent is a carrier
1.
A
both parents are carriers
2.
B
3.
C
both parents are homozygous recessive
4.
D
at least one parent is homozygous dominant
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
I. Incomplete Dominance
 The heterozygous phenotype is an
intermediate phenotype between the two
homozygous phenotypes.
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
II. Codominance
 Both alleles are expressed in the
heterozygous condition.
 Sickle-cell disease is one example.
Section 2
Complex Inheritance and Human Heredity
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
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
III. Multiple Alleles
 A. Human blood
 Blood groups in
humans
 ABO blood groups
have three forms
of alleles.
 (codominance and
multiple alleles
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
B. Coat Color of Rabbits
 Multiple alleles can demonstrate a hierarchy
of dominance.
 In rabbits, four alleles code for coat color: C
(C=full color), cch, ch, and c (recessive,
albino).
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
IV. Epistasis
 Variety is the result of one allele hiding the
effects of another allele.
 Coat color
 E=dark pigment
B=how dark
 EEBB and EeBb =black
 EEbb or Eebb =brown
 eebb, eeBb, eeBB= yellow (e masks B)
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
V. Sex Determination
 A. Sex chromosomes
determine an
individual’s gender.
 All cells in the body
except sex contain 46
chromosomes
 Sex chromosome
(#22) and last is
gender
• Gender is determined by combination of sex
chromosomes in the egg and sperm.
• The shapes are different so little to no cross
over.
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
B. 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.
 In females, one X chromosome is inactivated in
each cell. The inactivated X chromosome is
visible in stained cells as a Barr body.
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
VI. Sex-Linked Traits
 Genes located on the X chromosome
 males only have 1 X-affected by recessive
more than females
 Red-green color blindness
 Some traits seem sex linked but are not
(male baldness is dom in males, rec in
Sex-Linked Traits
females)
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
VII. Polygenic Traits
 Polygenic traits arise from the interaction of
multiple pairs of genes.
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
VIII. Environmental Influences
 Environmental factors influence an
organism’s phenotype
 Diet and exercise
 Sunlight and water
 Temperature
Section 2
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
IX. 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
Complex Inheritance and Human Heredity
Section 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
1.
2.
3.
4.
A
B
C
D
Chapter
Complex Inheritance and Human Heredity
Section 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
1.
2.
3.
4.
A
B
C
D
Chapter
Complex Inheritance and Human Heredity
Section 2 Formative
Questions
Which is an example of a polygenic trait?
A. blood type
B. color blindness
C. hemophilia
D. skin color
1.
2.
3.
4.
A
B
C
D
Section 3
Complex Inheritance and Human Heredity
Chromosomes and Human Heredity
I. 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.
Section 3
Complex Inheritance and Human Heredity
Chromosomes and Human Heredity
II. Telomeres
 Telomere caps consist of DNA associated
with proteins.
 Serves a protective function for the structure
of the chromosome
Section 3
Complex Inheritance and Human Heredity
Chromosomes and Human Heredity
III. Nondisjunction
 Cell division during which sister chromatids
fail to separate properly
 If one sex cell gets an extra, another gets
one less. Random which is fertilized.
 Down syndrome, also called trisomy 21
• Nondisjunction in sex chromosomes
– XX =normal
– X0=Turners
– XXX=nearly normal
XY= normal
XXY=Klinefelters
XYY=nearly normal
OY=fatal before birth
Turners-infertile, thicker neck
Klinefelters-may have some female characteristics
• IV. Fetal testing
– Amniocentesis=chromosome abnormalities and
defects
– Chorionic villus sampling=genetic defects and
chromosome abnormalities
– Fetal blood sample=genetic abnormalities, fetal
blood problems, can give medications before birth
Chapter
Complex Inheritance and Human Heredity
Section 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
1.
A
2.
B
pedigree.
3.
C
4.
D
Chapter
Complex Inheritance and Human Heredity
Section 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
1.
2.
3.
4.
A
B
C
D
Chapter
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
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
1.
2.
3.
4.
A
B
C
D
Chapter
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
1.
2.
3.
4.
A
B
C
D
C. a cherry-red spot on the back of the eye
D. vision problems
Chapter
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.
1. trait.
A
C. The individual is heterozygous for the
D. There is a mutation in the dominant
2.
B
3.
C
gene.
4.
D
Chapter
Complex Inheritance and Human Heredity
Chapter Assessment
Questions
What does the top horizontal
line between numbers 1 and 2
in the figure indicate?
A.
B.
C.
D.
1 and 2 are siblings
1 and 2 are parents
1 and 2 are offspring
1 and 2 are carriers
1.
2.
3.
4.
A
B
C
D
Chapter
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
1.
2.
3.
4.
A
B
C
D
Chapter
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 1.
2.
D. one extra chromosome on pair 123.
4.
A
B
C
D
Chapter
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
1.
2.
3.
A
B
C
Chapter
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
1.
2.
3.
A
B
C
Chapter
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.
B.
C.
D.
codominance
dosage compensation
epistasis
sex-linked
1.
2.
3.
4.
A
B
C
D
Chapter
Complex Inheritance and Human Heredity
Standardized Test
Practice
Why are males affected by recessive
sex-linked traits more often than are females?
A. Males have only one X chromosome.
B. Males have two X chromosomes.
1.
A
C. Males have only one Y chromosome.
2.
B
D. The traits are located on the Y chromosomes.
3.
C
4.
D
Chapter
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%
1.
2.
3.
4.
A
B
C
D
Chapter
Complex Inheritance and Human Heredity
Glencoe Biology Transparencies
Chapter
Complex Inheritance and Human Heredity
Image Bank
Section 1
Complex Inheritance and Human Heredity
Vocabulary
Section 1
carrier
pedigree
Section 2
Complex Inheritance and Human Heredity
Vocabulary
Section 2
incomplete
dominance
codominance
multiple alleles
epistasis
sex chromosome
autosome
sex-linked trait
polygenic trait
Section 3
Complex Inheritance and Human Heredity
Vocabulary
Section 3
karyotype
telomere
nondisjunction
Chapter
Complex Inheritance and Human Heredity
Animation
 Visualizing Nondisjunction
Chapter
Complex Inheritance and Human Heredity