Download Name - Humble ISD

Name _____________________________________________________________
Test Date _Tues, 2/14___
UNIT 10 – THE HUMAN GENOME
I. HUMAN GENETICS
(pp. 341-343)
A. Human Somatic Cells
 ____________ cells are ___________ or ______.
 Each cell contains ______ chromosomes, or ______ pairs of chromosomes.
o Of the 23 pairs _____ are ____________ ,contain the same genes in the same order, and are called
_______________
o The 23rd pair of chromosomes are the _______ chromosomes.
 Female= XX
 Male = XY
B. Human Gametes
 Gametes are _________, or ____, and contain ______ chromosomes.
 Female gametes are ______ cells made in the _________ in the process of meiosis
 Male gametes are _________cells made in the __________ in the process of meiosis
 Egg cells can only contain an X chromosome
 Sperm cell produced has a ____% chance of containing a ____ and a _____% chance of containing a ____
o The ________ determines the sex of the offspring.
C. Analyzing Human Chromosome Numbers
1. Nondisjunction - Abnormal numbers of chromosomes in ___________ result in genetic disorders called
_____________________.
 _______________________, which means _”_________________________”.
 A chromosome pair fails to separate correctly in _____________ so the gametes produced have an
abnormal _____________________________________________.
 Number disorders are _________ inherited; therefore, they ________________ be predicted with
____________________________
2. Karyotypes
 A photograph of _____________________________
 Cells are stopped during _________________ and are stained, photographed and the photograph is
enlarged.
 The chromosomes are cut out and arranged in ________________ pairs in size order, with the
__________ chromosomes making up the 23rd pair.
 Used to detect ____________ disorders and to determine the ____________ of an unborn child.
 Do not detect abnormal ______________; therefore, a normal karyotype
does not guarantee a ____________ child!
II. HUMAN GENETIC DISORDERS – NUMBER DISORDERS
(pp. 352,
353)
A. Autosomal Number Disorders
 Most are ___________.
 The only autosomal number disorder that allows survival into adulthood is ________________________
1. Down syndrome
 Known as __________________________ because there are _____ chromosomes at the _______
position, instead of _____.

Individuals have characteristic facial features; growth, behavior, and mental development are all affected.

There is also a higher risk of ______________________ heart defects.

The incidence of babies with Down syndrome is much higher in ____________ mothers.
B. Sex Chromosome Number Disorders
1. Turner Syndrome
 Called ___________

Because individuals lack
_________________________________
 ________________, typically ____________ in stature,
underdeveloped sexually, _____________, with a normal life
expectancy.
2. Klinefelter Syndrome
 Called __________.
 Symptoms do not appear until ______________ at which time
affected ___________ show poor sexual development and
infertility.
 Treated with _____________________. Normal life
expectancy.
III. ANALYSIS OF HUMAN INHERITANCE
A. Punnett Squares & Multiple Alleles (pp. 345-346)
1. multiple alleles; ___________________ alleles.
 An example of this is ABO blood groups. There are _____ alleles for this gene. Two of the alleles,
____ and _____ are co-dominant, meaning _______________________ if present. The third allele,
____, is recessive, meaning it will only show if the genotype is _____.
 Each individual inherits ____alleles for this gene, one from _________ and one from ________.
The possibilities for blood group genotypes and phenotypes are:
Phenotype
Genotype
Type A blood
Type B blood
Type AB blood
Type O blood
1. A couple preparing for marriage have their blood typed. Both are AB. They ask you what types of blood their
children may have. What would you tell them?
Cross: __________________________________
Phenotype Ratio: ________________________________________
2. An old, rich couple die in an accident. Soon a man shows up to claim their fortune, saying he is the long-lost son
who ran away with a circus as a boy. Other relatives say he is lying. Hospital records show the couple'’ blood
types were AB and O. The claimant is O.
Cross: __________________________________
Is he an imposter? _______________
2. 2 different couples gave birth at the same time. One baby has blood type O and the other baby has blood type A.
The nurses can not remember which baby goes with which parents. The first set of parents, the Lam’s have blood
type A & blood type B. The second set of parents, the Buck’s have blood type A and blood type AB. Which baby
belongs to which parent?
Lam’s: baby with blood type __________
Buck’s: baby with blood type __________
B. Pedigrees
 A diagram that follows the inheritance of a single __________ through several ________________ of a family.
 Males are represented by _______________
 Females, by __________________.
 Individuals with the trait are represented with ___________ figures.
 Individuals shown with unshaded figures _______________________________.
 Vertical lines connect _______________ and _________________.
 Horizontal lines connect ______________ or _________________.
 Children are placed in ________________, from ____________ to _______________.
1. The following pedigree shows the inheritance of a recessive trait.
a.
b.
c.
d.
e.
How many generations are shown in this pedigree? _______________
How many children did Parents I1 and I2 have? ________ How many boys? _______ Girls? ________
How many children did Parents II1 and II2 have? ________ How many boys? _______ Girls? ________
Key: _______________________________________________________________________
To solve a pedigree: Label all ________________________________________________ first!
2. Determine the genotype of all individuals in this pedigree showing the inheritance of red hair, a recessive
trait.
Key: ___________________________________________________________________
3. Determine the genotype of all individuals in the following pedigree showing the inheritance of a dominant
trait.
Key: __________________________________________________________________
IV. INHERITED HUMAN GENETIC DISORDERS
A. Gene Mutations
 __________________________________________________________.
 Causes Inherited human genetic disorders
B. Types of Inherited Genetic Disorders
1. Autosomal Genetic Disorders – Gene mutation is on any chromosome other than ______________________.
2. Sex-Linked Disorders – Mutated gene is on the _____ chromosome
V. GENETIC DISORDERS - AUTOSOMAL DISORDERS
(pp. 345-348)
 Most genes are carried on the _________________, ______ chromosomes other than the sex chromosomes.
 Most genetic disorders are ____________________ disorders.
 These disorders affect males and females _______________ and are due to _____________ mutations.
 Autosomal disorders can be divided into three groups based on the pattern of inheritance.
A. Autosomal Recessive Disorders
1. Albinism – Characterized by failure to produce pigment, _______________. Affected individuals lack coloration
in __________, __________, and __________. Very susceptible to ________________. Symptoms appear
______________________ ______________ life expectancy.
2. Cystic Fibrosis – Characterized by excess __________________ in _______________, ________________
system. Symptoms appear just after birth and include frequent respiratory infections, poor nutrition. With
treatment, patients can survive to young adulthood. Cystic fibrosis is the most common _____________ genetic
disorder in the ____________________ among Caucasians.
B. Autosomal Co-Dominant Disorders
1. Sickle cell anemia is an autosomal co-dominant disorder that affects _________________ production.
Hemoglobin is the protein that binds __________________ to red blood cells.
a. Individuals with the normal genotype, AA, do not have the sickle cell allele and produce only normal
Hemoglobin.
b. Individuals that are SS produce abnormal hemoglobin that causes the red blood cells to “sickle”
when oxygen availability is decreased;
i. for example, in high altitudes or during periods of stress. Sickled RBCs are more fragile,
easily destroyed – results in lack of ____________ due to decreased ________ production
in cells, blockage of blood vessels, and severe pain. Shortened life expectancy. Most
common inherited disease in individuals of ____________ ancestry.
c. Heterozygotes (AS) produce both normal and abnormal hemoglobin and are said to have
____________________. They do not show symptoms of the disorder. In certain areas,
individuals with sickle cell trait have a benefit over individuals that lack the sickle cell allele because
they are resistant to __________________. Malaria is a serious, sometimes fatal disease spread
by ________________ that affects millions of people each year in ____________. This increased
malarial resistance has resulted in a very high incidence of AS individuals. If two heterozygotes
marry and have children, they have a ________% chance of having a child with sickle cell anemia.
C. Autosomal Dominant Disorders
1. Huntington’s Disease – Fatal genetic disorder in which symptoms do not show until ____________.
Characterized by deterioration of ______________________.
2. Achondroplasia - __________________
VI. GENETIC DISORDERS - SEX-LINKED DISORDERS
A. Sex-Linked Inheritance (pp.350, 351)
 “Sex-linked” if it is located on a sex chromosome (____ or _____).
 In humans, sex-linked genes are almost always located on the larger ____ chromosome.
o The _____ chromosome is much smaller and carries only a few genes related to male
_____________________.
o Females have ____ X chromosomes;
o Males have _____.
 Females will only show recessive traits located on the X chromosome if they are _homozygous recessive.
 Males will always show a recessive trait located on the X chromosome because he only has one X.
This results in __________ having a much higher incidence of sex-linked disorders.
1. Genotypes for sex-linked traits are written using the X and Y chromosomes to show path of inheritance.
 Example, male-pattern baldness is a sex-linked recessive trait. If H = normal head of hair and h =
baldness, bald male = _________; bald female = ____________.
o Females can be _____________ for sex-linked recessive disorders = ____________The
defective allele ___________________________!
o Males ____________________ be carriers for sex-linked traits because their 2nd sex
chromosome is the __________________!
2. Sex-Linked Punnett Squares –
 In sex-linked traits, probabilities for male and female offspring must be calculated separately
because traits are ________________________.
If a man with a full head of hair marries a woman who is heterozygous, what is the probability they would have a
son who would go bald? A daughter?
Key: ______________________________________
Cross: _____________________________________
Probability of bald daughter = ___________
Probability of bald son = ____________________
B. Sex-Linked Disorders – All of these disorders are sex-linked ____________________.
1. Color Blindness – Inability to differentiate and distinguish ________________.
2. Hemophilia – Missing an enzyme required for normal ___________________ - results in ____________________.
Treated with blood transfusions, injections of missing factor.
3. Duchenne’s Muscular Dystrophy – Symptoms develop at _________________. Muscles ________________
_________________, leading to eventual death. No available ________________ or ___________. Death usually
occurs before adulthood.
C. Examples
1. A colorblind female marries a man with normal vision. What is the probability of colorblind children?
Key: ______________________________________
Cross: _____________________________________
Probability of colorblind daughter = ____________ Probability of colorblind son = ____________
2. A genetics counselor interviews a couple with a family history of hemophilia to evaluate the possibility
of offspring with the disorder. The woman does not have hemophilia, but states that her father had
the disorder. The man is normal.
Key: ___________________________________________
Cross: ___________________________________
Probability of daughter with hemophilia = ___________
Probability of son with hemophilia = __________
3. The following pedigree shows the path of inheritance of hemophilia through several generations. Identify the
genotypes of each individual.
Key: ________________________________________________________________