Transcript Slide 1

Complex Inheritance and
Human Heredity
Section 1: Basic Patterns of Human Inheritance
Section 2: Complex Patterns of Inheritance
Section 3: Chromosomes and Human Heredity
Do you look like you mom or dad? Why?
Did you inherit more traits from one parent?
Click on a lesson name to select.
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
Pedigrees
 A diagram that traces the inheritance of a
particular trait through several generations
A Family Tree
•
To understand how traits are passed on from generation to generation, a pedigree, or a
diagram that shows the relationships within a family, is used. In a pedigree, a circle
represents a female, and a square represents a male. A filled-in circle or square shows that
the individual has the trait being studied. The horizontal line that connects a circle and a
square represents a marriage. The vertical line(s) and brackets below that line show the
child(ren) of that couple.
1.Which parent has
F= free earlobes f= attached
attached ear lobes?
2.How many children
do the parents have?
Which child has
attached ear lobes?
Go to
Section:
3.Which child is
married? Does this
child’s spouse have
attached ear lobes?
Do any of this child’s
children have
attached ear lobes?
Complex Inheritance and Human Heredity
Human genetics
Recessive Genetic Disorders
 A recessive trait
is expressed
when the
individual is
homozygous
recessive for the
trait.
Protein is not
made if you are
recessive!
Complex Inheritance and Human Heredity
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.
The Cause of Cystic Fibrosis
Chromosome
#7
CFTR
gene
The most common allele
that causes cystic fibrosis
is missing 3 DNA bases.
As a result, the amino acid
phenylalanine is missing
from the CFTR protein.
Normal CFTR is a chloride
ion channel in cell
membranes. Abnormal
CFTR cannot be transported
to the cell membrane.
The cells in the person’s
airways are unable to transport
chloride ions. As a result, the
airways become clogged with a
thick mucus.
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
Albinism
 Caused by altered genes (epistasis),
resulting in the absence of the skin
pigment melanin in hair and eyes.
 White hair
 Very pale skin
 Pink pupils
Complex Inheritance and Human Heredity
Basic Patterns of Human Inheritance
Karyotype Pictures of your chromosomes organized by size.
Homologues are put together. Extra or missing chromosomes can be
seen.
Male or female?
How many autosomes are there?
How many chromosomes?
Section 14-2
How many sex chromosomes?
Sex of the person?
How many autosomes are there?
How many chromosomes?
How many sex chromosomes?
Sex of the person? What is this called?
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
Codominance
 Both alleles are expressed in the
heterozygous condition.
 Blood type demo and worksheet
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
N=normal S=sickle
Sickle-cell Disease –Codominant
3 genotypes: NN=normal
SS=sickle NS = heterozygous
Normal red blood cell
 Changes in hemoglobin
cause red blood cells to
change to a sickle shape.
 People who are
heterozygous (NS) for
the trait have both
normal and sickleshaped cells
Malaria- relationship
Sickle cell
7766x
Figure 14-4 Blood Groups
Phenotype
(Blood Type
Genotype
Antigen on
Red Blood Cell
Safe Transfusions
To
From
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
Multiple Alleles
 ABO blood groups have three forms of
alleles. IA IB i
 Rh blood groups - Rh factor contains the Rh antigen and
can cause problems when given Rh- people were given
Rh+ blood. This trait is also controlled by multiple alleles
(8).
 Transfusion activity! - Who will survive?
Complex Inheritance and Human Heredity
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.
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
Coat Color of Rabbits
Chinchilla
Albino
Light gray
Dark gray
Himalayan
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
Incomplete Dominance
 The heterozygous phenotype is an
intermediate phenotype between the two
homozygous phenotypes.
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
Polygenic Traits
 Polygenic traits arise from the interaction of
multiple pairs of genes.
On a sheet of paper, construct a Punnett
square for the following cross: XX x XY. Fill in
the Punnett square. What does the Punnett
square represent? According to the Punnett
square, what percentage of the offspring
from this genetic cross will be males? What
percentage will be females?
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
Sex Determination
 Sex chromosomes
determine an
individual’s gender.
 Males XY
 Females XX
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
 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.
(Testes Determining Factor)
 Chromosome inactivation –one X in every female
cell is turned off
 Barr bodies –turned off X chromosome
FYI calico cats-only females
Sex- influenced traits - Baldness occurs more often in males
than in females. It could be due to the differences in male and
female hormones.
Complex Inheritance and Human Heredity
Complex Patterns of Inheritance
Sex-Linked Traits
 Genes located on the X chromosome (recessive)
 Red-green color blindness -limited color vision;
mostly in males Color blind test
 Hemophilia – no AHF (anti-hemophilic factor)
Also called bleeders disease.
Muscular Dystrophy- incorrect protein (dystrophin) Mutant
gene causes the wasting away of skeletal muscles. Many
types of MD. Duchenne’s is usually fatal by age 20 due to
cardiac failure. 1 in 4,000 males effected
Sex-Linked
Traits
Colorblindness
Father
(normal vision)
Colorblind
Normal
vision
Male
Female
Daughter
(normal vision)
Son
(normal vision)
Daughter
(carrier)
Son
(colorblind)
Mother
(carrier)
n = normal color vision
p = little color vision
1. What individuals
have normal vision?
2. Which people are
color-blind?
1
2
3. Which are carriers?
4
3
9
10
11
5
12
6
7
8
13
14
Complex Inheritance and Human Heredity
Environmental Influences on genes
 Environmental factors
 Diet and exercise
 Sunlight and water
 Temperature
 Karyotype—pictures of the pairs of
homologous chromosomes are arranged
in decreasing size. Used to identify
chromosome disorders.
Complex Inheritance and Human Heredity
Chromosomes and Human Heredity
Nondisjunction
 Cell division during which sister
chromatids fail to separate properly
 Down syndrome- Chromosome disorder where individuals
have an extra 21st chromosome. Also called trisomy 21. 1out
of 800 babies are born with this. Caused by non-disjunction
during meiosis.
Visualizing
Nondisjunction
• On a sheet of paper, construct a Punnett
square for the following cross: XXX x XY. Fill in
the Punnett square. How is this Punnett
square different from the first one you
constructed? How is this different from a
normal punnett square?
Disjunction disorders - Sex chromosomes do not separate properly
during meiosis.
1. Turner syndrome - XO genotype. Female is sterile.
2. Klinefelter syndrome - XXY genotype. Males are sterile with
immature sex organs and some female characteristics.
3. Metafemale - XXX genotype . Females tend to have learning
disabilities and may enter menopause early or have cycle irregularities.
Most have no affects from this.
What union of gametes would have produced the above disorders?
4. XYY - Normal male, but may be taller than average. Controversy
about these males being antisocial and aggressive and a link to some
crimes.
Complex Inheritance and Human Heredity
Complex Inheritance and Human Heredity
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
Chapter Resource Menu
Chapter Diagnostic Questions
Formative Test Questions
Chapter Assessment Questions
Standardized Test Practice
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Vocabulary
Animation
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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