Transcript Slide 1

The Equation
Sally Doe has 88% right now in Q1
What does she need to get on the final to
guarantee at least a B in the class?
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.
Match the disease to its description
_____Cystic fibrosis
_____Albinism
_____Galactosemia
_____Tay Sachs
_____Huntingtons
_____Achondroplasia
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.
 A dominant trait is expressed when the
individual is homozygous dominant or
heterozygous.
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Huntington’s Disease
 Caused by the inheritance of a faulty
dominant allele of a crucial neural protein
(normal version is recessive)
 Person is normal until age 45-50 when
neural degeneration starts causing mental
deterioration and lack of ability to move body
 100% fatal
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Achondroplasia
 Caused by the inheritance of a faulty
dominant allele for bone growth which causes
person’s bones to stop growing prematurely
 Causes short arms and legs / large relative
head size, but no other defects (person is
normal otherwise)
 2 people w/ achondroplasia can have normal
height children
Chapter 11
Complex Inheritance and Human Heredity
Match each symbol to its meaning in pedigree diagrams:
___ Box
___ Circle
___ Horizontal line
___Vertical line
___Unshaded box or circle
___Shaded box or circle
___Half filled in box or circle
___Strike across box or circle
Create a pedigree for this scenario:
Chapter 11
Complex Inheritance and Human Heredity
11.1 Basic Patterns of Human Inheritance
Pedigree Analysis
 A diagram that traces the inheritance of a
particular trait through several generations
Pedigree symbols
Chpt11.2
• Non-Mendellian genetics:
– Incomplete dominance
– Co-dominance
– Sex linked traits
– Polygenic genetics
Define / explain what incomplete
dominance is by describing an example
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.
Genotype+
Incomplete Dominance
One allele is active (red
color allele)
Other allele is defective
(white = no color being
made)
In heterozygote, one
functioning allele is not
enough to make
phenotype completely
that trait
Similar to normal
dominance, but in that
case one functioning
allele makes enough
protein to make
heterozygote phenotype
look same as
homozygous dominant
Define / explain what Codominance is by
describing an example:
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Codominance
 Both alleles are expressed in the
heterozygous condition.
Co-Dominance
Two alleles, both co-dominant (both will coexist)
Ex. Roan Cattle
RR alleles = red
WW alleles = white
RW alleles = red + white hairs on same cow
 Ex Human blood types
 3 Alleles: IA IB i
 A (IA) and B (IB) are codominant to each other
 O (i) is recessive to both A and B
Draw a sketch of what each red blood cell
would look like regarding surface proteins &
what antibodies the person has present (if
any):
• Human blood types
• 3 alleles present in the gene pool (A, B, O)
• Each person can have two alleles do there
are 4 possible blood types:
A, B, AB, O
A= AA or AO
B= BB or BO
AB = AB
O= OO
Co-dominance: Blood types
Transfusions
When figuring out transfusions, only pay
attention to the antibodies in the recipient
Ex. Type A person in accident…what blood
types ok for them to get?
A person has anti B antibodies…so no
type B proteins allowed
So A person can get: O, A
Non
clumpy
is good!!
Clumpy=
dead!!
For lab: add blood, add specific antibody…if clumping =
that specific protein is present
Explain why Colorblindness is more rare in
females
Sex linked inheritance
• Although the anatomical and physiological
differences between women and men are
numerous, the chromosomal basis of sex is
rather simple.
• In human and other mammals, there are two
varieties of sex chromosomes, X and Y.
– An individual who inherits two X chromosomes
usually develops as a female.
– An individual who inherits an X and a Y chromosome
usually develops as a male.
Chapter 11
Complex Inheritance and Human Heredity
11.2 Complex Patterns of Inheritance
Sex Determination
 Sex chromosomes
determine an
individual’s gender.
SRY gene on Y
chromosome
only
In individuals with the SRY gene (sex determining region of the Y
chromosome), the generic embryonic gonads are modified into testes.
Activity of the SRY gene triggers a cascade of biochemical, physiological,
and anatomical features because it regulates many other genes.
In addition, other genes on the Y chromosome are necessary for the
production of functional sperm.
In individuals lacking the SRY gene, the generic embryonic gonads develop
into ovaries.
Lots of genes are on the X
chromosome, not only the
“girl” stuff, but stuff all
humans need to survive
•In addition to their role in determining sex, the X chromosome, has genes for
many characters unrelated to sex…
•(.Hair, eyes, clot formation, muscle development, +others)
Sex linked recessive disorders:
-red green color blindness
-hemophilia
-Duchenne muscular dystrophy
If a sex-linked trait is due to a recessive allele, a female will have this
phenotype only if homozygous. (Heterozygous females will be carriers.)
Because males have only one X chromosome (hemizygous), any male
receiving the recessive allele from his mother will express the trait.
The chance of a female inheriting a double dose of the mutant allele is
much less than the chance of a male inheriting a single dose.
Therefore, males are far more likely to inherit sex-linked recessive
disorders than are females.
What does “Polygenic” mean? How do you
know if a trait is polygenic?
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.
Explain how 2 alleles for skin color can
produce a spectrum of human skin tones.
Show proposed genotype for lightest skin
tone person possible vs. darkest skin tone
person possible
Polygeneic Inheritance
More than one gene involved with the trait
Ex. Hu skin color
-3 homologous
chromosomes have
gene for color on them
-2 alleles (dark + light)
What is a karyotype?
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.
Draw a karyotype of a female organism in which 2n=8
showing trisomy of chromosome 3
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
Explain the cause of Down Syndrome
Trisomies
21: Down Syndrome
18: Edwards Syndrome
13: Patau syndrome
Chapter 11
Complex Inheritance and Human Heredity
Explain the benefits and risks
associated with each fetal test
Test
Amniocentesis
Chorionic villus
sampling
Ultrasound
Benefit
Risk
How it works
 Prenatal diagnosis of genetic and congenital abnormalities.
 Invasive techniques.
 1. Amniocentesis.
Draw amniotic
fluid, check cells
DNA for genetic
problems
2. Chorionic Vilus
sampling
Take tiss. Sample
of placenta and
check DNA
 Noninvasive techniques.
 Ultrasound imaging.
Chapter 11
Complex Inheritance and Human Heredity
11.3 Chromosomes and Human Heredity
Telomeres
Telomere: End of a
chromosome. In vertebrate
cells, each telomere
consists of thousands of
copies of the same DNA
sequence, repeated again
and again
This region of repetitive
DNA at the end of a
chromosome protects the
chromosome.
Fetal testing Product:
Describe:
-How each test works (Karyotype, ultrasound, CVS, Amnio)
-Benefits of the test
-Risks of the test
Choices:
-”illustrated chart”
-Medical advertisements (w/ risks as fine print!)
-Debate dialogue of a “Pro” testing person for each vs. a
“con” testing person.
Grand Finale of Q1 Bio: Spidey doing Napolean Dynamite dance!!!
Chapter 11
Complex Inheritance and Human Heredity
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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