Deck 4: Pedigree Analysis in Human Genetics

Question 1

Hemophilia was a significant issue in the life of

A) Abraham Lincoln.
B) Olympic volleyball star Flo Hyman.
C) Noah.
D) the family of the last tsar of Russia.
E) King George III of England.

Answer 1

D

Question 2

The main problem for sufferers of cystic fibrosis is

A) abnormal hemoglobin.
B) elevated levels of cholesterol.
C) mucus blocking ducts of glands.
D) missing DNA repair enzymes.
E) formation of cysts in kidneys.

Answer 2

C

Question 3

Almost all cases of alkaptonuria, a rare genetic disorder, arise as the result of mating between two unaffected parents. Why?

A) It is a co-dominant disorder.
B) It is a dominant disorder.
C) It is a recessive disorder.
D) It is a disorder controlled by multiple alleles
E) It is a disorder that only affects mature adults.

Answer 3

C

Question 4

Which of the following is NOT a symptom of Marfan syndrome?

A) Vision problems
B) Blood vessel defects
C) Loose joints
D) Short stature
E) All of these are symptoms of Marfan syndrome

Question 5

Camptodactyly

A) causes bent, immobile little fingers.
B) is inherited as a dominant trait.
C) shows less than complete penetrance.
D) shows varying expressivity.
E) is characterized by all of these.

Question 6

If a man expresses an X-linked recessive trait, we can draw the following conclusion:

A) His father carried the mutation.
B) His father transmitted the trait to his son.
C) His mother did not carry the mutation gene.
D) His mother was heterozygous or homozygous for the trait.
E) All his brothers will also show the trait.

Question 7

Which of the following is a goal of pedigree analysis?

A) To determine dominance and recessive patterns.
B) To determine if a gene is sex-linked or autosomal.
C) To determine gene loci.
D) To determine dominance and recessive patterns and if a gene is sex-linked or autosomal.
E) To determine gene loci and if a gene is sex-linked or autosomal.

Question 8

Which of the following is NOT a characteristic of an autosomal recessive trait?

A) All of the children of two affected individuals are affected.
B) If two individuals are heterozygous, the risk of having an affected child is 1:4.
C) For rare traits, affected individuals have unaffected parents.
D) Every affected individual has at least one affected parent.
E) All of these are characteristic of an autosomal recessive trait.

Question 9

The gene responsible for Marfan syndrome encodes a protein associated with

A) heart muscle.
B) connective tissue.
C) fat tissue.
D) red blood cells.
E) nervous tissues.

Question 10

In autosomal dominant inheritance

A) the trait often skips generations.
B) about one-fourth of the progeny in a pedigree will show the trait.
C) two affected individuals may have unaffected children.
D) males are more affected than females.
E) a deleterious phenotype is always produced.

Question 11

Y-linked traits are

A) known as hemizygous traits.
B) known to skip alternate generations of males.
C) carried only by males and transmitted only to males.
D) known to skip alternate generations of males and are carried only by males and transmitted only to males.
E) known as hemizygous traits and are carried only by males and transmitted only to males.

Question 12

Which one of the following is NOT usually a symptom of cystic fibrosis?

A) Low fertility or infertility
B) Frequent respiratory infections
C) Difficulty breathing
D) Loss of pancreatic function
E) Problems with hearing and vision

Question 13

If a pedigree of several generations shows only females affected by a particular trait, what can be ruled out?

A) Autosomal recessive inheritance
B) X-linked dominant inheritance
C) Y-linked inheritance
D) X-linked recessive inheritance
E) None of these can be ruled out

Question 14

Dystrophin is a protein that normally

A) shortens and lengthens to produce muscle contraction.
B) carries signals into muscle cells to initiate contraction.
C) strengthens the attachment between muscle proteins and the plasma membrane.
D) helps provide energy for muscle contraction.
E) signals muscle cells to divide.

Question 15

If a trait is inherited in an autosomal recessive fashion, which of the following is not true?

A) Both sexes are equally affected.
B) The trait will not occur in offspring if one of the parents is homozygous dominant.
C) About one-fourth of the offspring of two heterozygotes will be affected.
D) The trait often appears in the progeny of unaffected parents.
E) Two affected individuals can have an unaffected child.

Question 16

Parents with normal pigmentation have an albino child. What is the chance that their next child will have normal pigmentation?

A) 0 percent
B) 25 percent
C) 33 percent
D) 50 percent
E) 75 percent

Question 17

Amal has a serious metabolic disorder known as PKU. His sister has the same disorder. Neither of Amal's parents have the disorder. What is the most likely inheritance pattern of this disorder?

A) Autosomal dominant
B) Autosomal recessive
C) X-linked dominant
D) X-linked recessive
E) It is not possible to tell the inheritance pattern from this information.

Question 18

Approximately how many Y-linked genes have been discovered?

A) None
B) 10
C) 36
D) 100
E) 300

Question 19

Two phenotypically normal parents have six children. Two daughters and two sons have the same genetic disease. This would be the expected situation for

A) hemophilia.
B) cystic fibrosis.
C) Marfan syndrome.
D) hypophosphatemia.
E) all of these.

Question 20

A child is born with a lethal dominant allele. This would seem to be impossible since either parent, had they possessed this allele, would have suffered its lethal effects. What is a possible explanation?

A) The child's allele is a spontaneous mutation that neither parent had to deal with.
B) The allele could have varying expressivity and not always be lethal.
C) The allele could have delayed onset.
D) All of these are possible.
E) None of these is possible.

Question 21

Mendel's laws apply to all sexually reproducing organisms. Therefore, the basic methods of genetic analysis in humans and other organisms is the same.

Question 22

The basic method of genetic analysis in humans is ____________________ rather than experimental.

Question 23

If a man and his wife are both homozygous for a disease-causing recessive gene, then ____________________ of their children will be affected.

Question 24

Human traits are controlled only by the genetic material found in the 46 chromosomes.

Question 25

The phenotypes of a trait controlled by the same gene are not always identical.

Question 26

Valeria has a serious disorder called fragile X syndrome and her brother does not have the disorder. Her mother does not have the disorder but her father does. What is the most likely inheritance pattern for fragile X syndrome?

A) Autosomal dominant
B) Autosomal recessive
C) X-linked dominant
D) X-linked recessive
E) Y-linked recessive

Question 27

What are the chances that a woman who is color blind will have a son who is color blind?

A) 0 percent
B) 25 percent
C) 50 percent
D) 75 percent
E) 100 percent

Question 28

All genes are expressed in either the prenatal or newborn stages.

Question 29

Autosomal dominant traits are inherited from affected parents.

Question 30

The basic method of genetic analysis in humans requires a ____________________ of several generations.

Question 31

More than one mode of inheritance can be seen for a single trait.

Question 32

The frequency of heterozygotes for cystic fibrosis shows ethnic variations.

Question 33

A color-blind man has a son who is also color blind. The son inherited the condition from his ____________________.

Question 34

Color blindness only occurs in males.

Question 35

Duchenne muscular dystrophy and Becker's muscular dystrophy represent allelic forms of the same X-linked gene.

Question 36

The analysis of a pedigree is complete when the information in the pedigree supports the hypothesis formed by the geneticist.

Question 37

Adults who have children who have died from lethal recessive disorders are most likely ____________________.

Question 38

The underlying problem with cystic fibrosis is

A) the inability to transport chloride ions.
B) mutations in the hemoglobin molecule.
C) defective ganglioside molecules.
D) the inability to metabolize certain amino acids.
E) abnormal fat deposits around the heart.

Question 39

People with cystic fibrosis have difficulty digesting food properly.

Question 40

Variation in expressivity and penetrance of genes is due to the effects of other genes and the environment.

Question 41

Huntington's disease, a severe autosomal dominant neurological disorder, shows a ____________________ in its expression.

Question 42

Explain the inheritance of mitochondrial DNA and how a person inherits a mitochondrial genetic disease.

Question 43

The most common forms of color blindness cause inability to properly perceive the colors ____________________ and ____________________.

Question 44

The gene that codes for the connective tissue protein fibrillin is the gene that causes ____________________.

Question 45

How would you distinguish between a trait that is X-linked dominant trait and one that is autosomal dominant?

Question 46

Genetic diseases transmitted only by a mother to both sons and daughters result from ____________________ genes.

Question 47

The proportion of individuals in a population expressing a trait when they have the appropriate genotype represents the percent of ____________________ for the trait.

Question 48

The degree to which a trait is expressed in individuals is the ____________________ of the trait.

Question 49

Tomas has a rare genetic defect that causes him to snore excessively. Tomas's partner, Glora, does not have this problem. Tomas's sister, Eloise, also does not have this problem. Eloise has a daughter who is normal and identical twin boys who snore excessively like Tomas. The parents of Tomas, Eloise, and Gloria are all normal. Draw a pedigree for this family. What is the mode of transmission of this defect?

Question 50

Is it easier to work out pedigrees for dominant traits than for recessive ones? What can complicate the analysis of dominant traits?

Question 51

Mitochondrial gene defects mainly cause myopathies (conditions affecting ____________________), and encephalomyopathies (conditions also affecting ____________________).

Question 52

A missing or ineffective chlorine ion transporter is the cause of ____________________.

Question 53

If a man and his wife are affected with a dominant trait, then ____________________ of their children could be unaffected.

Question 54

In pedigree analysis, is it always possible to determine the mode of inheritance for a trait? What factors can complicate this task?

Question 55

A defective form of the protein dystrophin is involved in the diseases __________ and ________.

Question 56

When affected males produce all affected daughters and no affected sons, the genetic disease is likely to be ____________________.

Question 57

A large family exhibits a previously undiscovered trait: green hair. One parent has the trait as do 6 of their 12 children (50%). (a) Satisfy yourself that this result could be produced by either one of two situations: Green hair is caused by a dominant allele, and the green-haired parent has one copy of that allele; OR green hair is a recessive trait; the green-haired parent is homozygous and the other parent is heterozygous. (b) How might we determine which one of these possibilities is true?

Question 58

If Marfan syndrome results in death, it is usually due to rupture of the ____________________.

Question 59

Compared to experimental organisms such as the garden pea, why is it that humans are poor subjects for genetic investigations?

Question 60

How do each of the following affect the expression of single gene traits: incomplete dominance, expressivity, penetrance?