Deck 4: Pedigree Analysis in Human Genetics

Question 1

A blood test cannot determine if a person is a carrier of Tay-Sachs disease because the mutant allele is undetectable.

Answer 1

False

Question 2

Phenotypic variation can occur in traits controlled by the same allele.

Answer 2

True

Question 3

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) the aa phenotype will be affected

Answer 3

C

Question 4

If a man expresses an X-linked recessive trait,____.

A) all of his brothers will also express it
B) his father transmitted the trait to him
C) his father carried the trait
D) all of his sisters will also express it
E) his mother was heterozygous or homozygous for the trait

Question 5

A pedigree is always able to provide enough information to rule out all but one possible pattern of inheritance.

Question 6

Approximately ____ Y-linked genes have been discovered.

A) 10
B) 20
C) 60
D) 80
E) 120

Question 7

Camptodactyly causes ____.

A) bent, immobile little fingers
B) breathing difficulties
C) loose joints
D) muscle deterioration
E) near-sightedness

Question 8

Almost all cases of cystic fibrosis,a(n)____ genetic disorder,are the result of mating between two unaffected parents.

A) mitochondrial
B) autosomal dominant
C) autosomal recessive
D) X-linked dominant
E) X-linked recessive 

Question 9

The frequency of heterozygotes for cystic fibrosis shows ethnic variations.

Question 10

Males never give an X chromosome to any of their sons.

Question 11

One goal of pedigree analysis is to determine ____.

A) what diseases a family will display
B) if two people are related
C) gene loci
D) whether a gene has a dominant or recessive pattern of inheritance
E) what treatment a person should undergo

Question 12

Abraham Lincoln's son,Robert,showed no signs of Marfan syndrome.

Question 13

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

Question 14

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 tissue

Question 15

Most of those affected with an autosomal dominant genetic disorder are homozygous for that trait.

Question 16

Duchenne muscular dystrophy and Becker's muscular dystrophy are caused by different mutations in the same X-linked gene.

Question 17

If a pedigree analysis suggests that an autosomal or X-linked inheritance pattern is equally likely,then additional genetic testing is needed to identify the pattern of inheritance.

Question 18

Y-linked traits are ____.

A) known as homozygous traits
B) known to skip generations in males
C) carried only by males and transmitted only to males
D) carried only by females, but are never expressed
E) passed on to only 50% of female progeny

Question 19

If two phenotypically normal parents have six children,and two daughters and two sons have the same genetic disorder,that disorder is most likely to be ____.

A) hemophilia
B) cystic fibrosis
C) Marfan syndrome
D) muscular dystrophy
E) color blindness

Question 20

The chance of a child having albinism when both of his parents are heterozygous for the disorder is ____ percent.

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

Question 21

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

Question 22

Mitochondrial gene defects most often affect the ____________________ and the ____________________.

Question 23

A mutation in the gene that codes for a connective tissue protein called fibrillin causes ____________________.

Question 24

Common recessive alleles present in a family can result in a pedigree that looks like ____ inheritance.

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

Question 25

The probability that a disease phenotype will appear when a disease-related genotype is present is called ____________________.

Question 26

One characteristic of an autosomal dominant trait is that ____.

A) 50% of individuals with two affected parents will be affected
B) if two affected individuals are homozygous, the risk of having an affected child is 1:4
C) heterozygous fathers will always have affected daughters
D) every affected individual has at least one affected parent
E) mothers always pass the trait on to their sons

Question 27

The X and Y chromosomes ____.

A) are responsible for autosomal recessive inheritance
B) will lead to color-blindness in all carriers
C) are found paired with all 22 autosomal chromosomes
D) are responsible for albinism
E) play major roles in determining the sex of an individual

Question 28

Mucus production that blocks ducts of certain glands and lung passages is a symptom of ____________________.

Question 29

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

Question 30

If both parents are homozygous for a disease-causing recessive gene,____________________ of their children will be affected.

Question 31

Color blindness is an inherited disorder passed from ____________________ to child.

Question 32

When affected males produce all affected daughters and no affected sons,the pattern of inheritance is likely to be ____________________.

Question 33

Hemophilia is characterized by ____.

A) defects in the mechanism of blood clotting
B) an extremely low blood iron level
C) jaundice of the eyes and skin
D) muscular weakness and atrophy
E) breathing difficulties

Question 34

The initial circumstance that led some to believe that Abraham Lincoln had Marfan syndrome was that ____ had the disease.

A) one of Lincoln's descendants
B) Lincoln's sister
C) a descendent of Lincoln's great-great-grandfather
D) DNA analysis on Lincoln's skull determined that he
E) Photographs of Lincoln provided physical evidence that he

Question 35

There are ____ basic patterns of Mendelian inheritance.

A) three
B) four
C) five
D) six
E) seven

Question 36

A trait shows ____ if the phenotype of that trait is present in less than 100% of those with the related genotype.

A) autosomal recessive inheritance
B) autosomal dominant inheritance
C) incomplete dominance
D) incomplete penetrance
E) incomplete expressivity

Question 37

If a pedigree of several generations shows only females affected by a particular trait,it cannot be a(n)____ trait.

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

Question 38

Mitochondria are transmitted from mothers to ____.

A) all of their daughters through the cytoplasm of the egg
B) all of their sons through the cytoplasm of the egg
C) all of their children through the cytoplasm of the egg
D) 50% of their children through the X chromosome
E) 50% of daughters through the X chromosome

Question 39

The phenotype of ____ does not develop until adulthood.

A) muscular dystrophy
B) Marfan syndrome
C) cystic fibrosis
D) hemophilia
E) Huntington's disease

Question 40

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

Question 41

A marriage between two related individuals,such as first cousins,is called ____________________.

Question 42

Define the terms penetrance and expressivity and explain how they affect the expression of single gene traits.

Question 43

Explain why color-blindness is much more common in males than in females.

Question 44

Individuals with Marfan syndrome experience an eyesight problem called ____________________.

Question 45

Identify the pattern of Mendelian inheritance represented in the pedigree above and explain how you made this determination.

Question 46

If a man expresses an X-linked recessive trait,his ____________________ was either homozygous or heterozygous for the trait.

Question 47

Define the term hemizygous and explain how the hemizygous condition relates to sex-linked inheritance.

Question 48

Draw and label a pedigree of Noah and his parents based on the theory that he was affected with an autosomal recessive genetic disorder.Explain your drawing and briefly describe the disorder that Noah might have had.

Question 49

Cytoplasmic organelles that convert energy from food molecules in ATP and are transmitted from mothers to all their children through the cytoplasm of the egg are called ____________________.

Question 50

If an autosomal ____________________ allele is very common in a population,there is a chance that it will enter the pedigree from outside the family.

Question 51

Summarize the arguments,both for and against,for the hypothesis that Abraham Lincoln had Marfan syndrome.

Question 52

The variable phenotypic expression shown in camptodactyly results from the interaction of ____________________ and ________________factors.

Question 53

Lisa has a rare genetic defect that causes acute sun-sensitivity.Her mother has the defect,but her father does not.All of Lisa's siblings,two brothers and a sister,are also affected.All four siblings are married,but none of their spouses has the mutant gene.Draw a pedigree for this family.Identify and explain the most likely mode of transmission for this disorder.

Question 54

One goal of pedigree analysis is to discover whether the gene in question is located on an X or a Y chromosome or on a(n)____________________.

Question 55

List and explain at least three patterns of inheritance of an autosomal dominant trait.

Question 56

Czar Nicholas II of Russia and Queen Victoria's granddaughter,Alix,were the parents of a son with the genetic disorder affecting the mechanism of blood clotting called ____________________.

Question 57

The phenotype in homozygous dominant individuals affected with an autosomal genetic disorder is often more severe than the ____________________ phenotype.

Question 58

Choose one of the basic patterns of Mendelian inheritance and draw and explain a three-generation family pedigree illustrating that pattern.

Question 59

Summarize the usefulness of the online catalog of human genetic traits developed and maintained by researchers at Johns Hopkins University.

Question 60

OMIM is an acronym that stands for ____________.