Question 1

(a) What is a direct-to-consumer genetic test? (b) What are some advantages of direct-to-consumer tests? (c) What are some disadvantages or problems associated with these tests? (d) Do you think states and/or the federal government should regulate direct-to-consumer genetic testing? Defend your position with facts and arguments.

Accepted Answer

(a) A direct-to-consumer genetic test is...

Question 2

The pedigree below shows the segregation of an autosomal recessive trait. If III-3 and III-4 marry and have a child, what is the probability that this child will show the trait? 1/4 B)  1/6 C)  1/8 D)  1/2 E)  2/3" class="answers-bank-image d-inline" rel="preload" >

Accepted Answer

A)   1/4
B)   1/6
C)   1/8
D)   1/2
E)   2/3F) C) and E)
G) B) and E)

Question 3

This form of prenatal testing is most commonly performed between the 15th week and 18th week of pregnancy.

Accepted Answer

A)   chorionic villus sampling
B)   preimplantation genetic analysis
C)   amniocentesis
D)   heterozygote screening
E)   presymptomatic screeningF) A) and B)
G) A) and C)

Question 4

Imagine that a human characteristic is determined by genotype only, with no environmental influence. Based on the amount of shared genetic information in MZ (monozygotic)  and DZ (dizygotic)  twins, what would you expect the concordance values to be in these two sets of twins?

Accepted Answer

A)   The concordance values would be near 100% for both types of twins.
B)   The concordance values would be near 50% for both types of twins.
C)   The concordance values should be close to 100% for MZ twins and a concordance value much less for DZ twins.
D)   The concordance values should be close to 50% for MZ twins and about 25% for DZ twins.
E)   The concordance values should be close to 25% for MZ twins and about 75% for DZ twins.F) D) and E)
G) A) and E)

Question 5

In pedigree analysis, the proband is:

Accepted Answer

A)   the individual having the trait or disorder from whom the pedigree is initiated.
B)   the medical geneticist who analyzes the pedigree to find the mode of inheritance for the disorder.
C)   the parents of the first child in the family to show the trait or disorder.
D)   one of the grandparents or great grandparents who are in the first generation of the pedigree.
E)   the most common software package that geneticists use to analyze pedigrees.F) B) and E)
G) A) and D)

Question 6

If the phenotype followed in Pedigree 3 is X-linked recessive, then what is the genotype of II-2? Assume no new mutations and complete penetrance.

Accepted Answer

A)   homozygous dominant
B)   heterozygous
C)   homozygous recessive
D)   hemizygous dominant
E)   hemizygous recessiveF) B) and E)
G) None of the above

Question 7

Which of the following is NOT correctly identified as an advantage is using amniocentesis?

Accepted Answer

A)   It can be used to detect chromosome abnormalities prenatally in the fetus.
B)   In some cases, it can be used to obtain fetal DNA so that tests can be done to determine if the fetus may have a particular genetic disorder.
C)   It can normally be done as early as the sixth week of pregnancy.
D)   It has a somewhat lower risk of complications than chorionic villus sampling.
E)   All of these are advantages with the use of amniocentesis.F) B) and C)
G) A) and B)

Question 8

Most pedigrees showing the hypothetical human trait show the following characteristics: 
• Males and females are equally affected.
• Two unaffected parents can have an affected child.
• In families in which the parents are unaffected but the children are affected, one-fourth of the children are affected.
What is the MOST likely mode of inheritance for this disorder?

Accepted Answer

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

Question 9

The pedigree below shows the segregation of an autosomal dominant trait. If IV-1 marries IV-5, what is the probability that their first child will be affected? Assume that the homozygous mutant genotype is viable and has the same phenotype as the heterozygote.

Accepted Answer

A)   1/4
B)   1/2
C)   3/4
D)   3/8
E)   1/8F) D) and E)
G) A) and C)

Question 10

The pedigree below shows the segregation of an autosomal recessive trait in humans. Unless there is evidence to the contrary, assume that individuals who marry into the family do not carry the recessive allele. If IV-1 and IV-2 marry, what is the probability that their first child will have this trait?

Accepted Answer

A)   1/12
B)   1/16
C)   1/24
D)   1/36
E)   1/8F) A) and B)
G) C) and E)

Question 11

Which statement is INCORRECT concerning an X-linked recessive trait in humans?

Accepted Answer

A)   An affected man often has phenotypically normal parents.
B)   All the sons of an affected woman will be expected to be affected.
C)   An affected woman almost always has an affected mother.
D)   An affected man usually has a mother who carries the recessive allele.
E)   A phenotypically normal woman whose father was affected is likely to be heterozygous for the condition.F) A) and E)
G) A) and C)

Question 12

A trait is caused by a rare dominant autosomal allele with full penetrance. Practically all individuals with the trait are heterozygous and result from matings between affected and normal individuals. What would be the expected concordance values for monozygotic and dizygotic twins?

Accepted Answer

A)   100% for both types of twins
B)   100% for monozygotic twins and 90% for dizygotic twins
C)   about 90% for both types of twins
D)   100% for monozygotic twins and 50% for dizygotic twins
E)   75% for monozygotic twins and 25% for dizygotic twinsF) C) and D)
G) A) and D)

Question 13

Is it possible that the characteristic in the pedigree below could be X-linked dominant? If so, what is the genotype of each individual? If not, explain why not, giving specific genotypes. Use alleles B and b.

Accepted Answer

The answer of Is it possible that the characteristic in...

Question 14

Is it possible that the characteristic in the pedigree below could be X-linked recessive? If so, what is the genotype of each individual? If not, explain why not, giving specific genotypes. Use alleles A and a.

Accepted Answer

The answer of Is it possible that the characteristic in...

Question 15

Phenylketonuria (PKU)  is an autosomal recessive condition that can lead to mental retardation. It is caused by an enzyme deficiency that interferes with phenylalanine metabolism, causing a by-product to accumulate to levels that are toxic to brain development. Intellectual disability due to PKU can be prevented by a special diet that strictly restricts intake of phenylalanine but the diet must be started soon after birth to be effective. Which of the following would be the MOST appropriate and cost-efficient way of identifying individuals who need the special diet?

Accepted Answer

A)   heterozygote screening
B)   newborn screening
C)   presymptomatic testing
D)   prenatal diagnosis
E)   amniocentesisF) A) and B)
G) A) and C)

Question 16

Explain what the following data say about the genetic and environmental influence on each characteristic. How did you interpret these data? (MZ = monozygotic twins and DZ = dizygotic twins.)    Concordance in  Trait  MZ  DZ  Right- or left-handedness 8075 Manic depression 8020\begin{array} { | l | c c } \hline & { 	ext { Concordance in } } \\hline 	ext { Trait } & 	ext { MZ } & 	ext { DZ } \\hline 	ext { Right- or left-handedness } & 80 & 75 \\hline 	ext { Manic depression } & 80 & 20 \\hline\end{array} Trait  Right- or left-handedness  Manic depression ​ Concordance in  MZ 8080​ DZ 7520​​

Accepted Answer

A)   Handedness and manic depression both have a strong genetic basis and little or no environmental basis.
B)   Handedness and manic depression are both strongly affected by environmental factors with little or no genetic basis.
C)   Handedness and manic depression are strongly affected by both environmental factors and genetic factors.
D)   Handedness is strongly affected by environmental factors with little or no genetic basis, while manic depression is significantly affected by genetic factors.
E)   Handedness is significantly affected by both environmental and genetic factors, while manic depression is significantly affected by environmental factors with little genetic basis. F) B) and D)
G) None of the above

Question 17

This form of prenatal testing is most commonly performed between the 10th week and 12th week of pregnancy and involves the insertion of a soft plastic into the vagina to obtain cells.

Accepted Answer

A)   chorionic villus sampling
B)   preimplantation genetic analysis
C)   amniocentesis
D)   heterozygote screening
E)   presymptomatic screeningF) All of the above
G) B) and D)

Question 18

If the pedigree below is for an autosomal recessive characteristic, which individuals are definitely heterozygous?

Accepted Answer

A)   I-1, I-2, II-2, II-4, II-5
B)   I-1, I-2, I-4, III-1
C)   I-1, I-2, II-4, II-5, III-1
D)   II-2, II-4, II-5, II-3
E)   II-2, II-4, II-5, III-1F) A) and C)
G) C) and D)

Question 19

Which of the following is NOT a characteristic of X-linked recessive traits in humans?

Accepted Answer

A)   More males than females are affected.
B)   Approximately one-half of the sons of a female carrier are affected.
C)   They cannot be passed from father to son.
D)   Phenotypically normal daughters of affected men are always carriers.
E)   Affected daughters always have an affected mother.F) A) and E)
G) All of the above

Question 20

A trait is caused by a rare recessive autosomal allele with full penetrance. Practically all individuals with the trait result from matings between normal individuals. What would be the expected concordance values for monozygotic and dizygotic twins?

Accepted Answer

A)   100% for both types of twins
B)   100% for monozygotic twins and 50% for dizygotic twins
C)   about 50% for both types of twins
D)   100% for monozygotic twins and 75% for dizygotic twins
E)   100% for monozygotic twins and 25% for dizygotic twinsF) A) and E)
G) A) and C)

Exam 6: Pedigree Analysis, Applications, and Genetic Testing

Is it possible that the characteristic in the pedigree below could be X-linked recessive? If so, what is the genotype of each individual? If not, explain why not, giving specific genotypes. Use alleles A and a.

Correct Answer
verified

This form of prenatal testing is most commonly performed between the 15th week and 18th week of pregnancy.

Correct Answer
verified

In pedigree analysis, the proband is:

Correct Answer
verified

Which statement is INCORRECT concerning an X-linked recessive trait in humans?

Correct Answer
verified

Which of the following is NOT a characteristic of X-linked recessive traits in humans?

Correct Answer
verified

If the phenotype followed in Pedigree 3 is X-linked recessive, then what is the genotype of II-2? Assume no new mutations and complete penetrance.

Correct Answer
verified

This form of prenatal testing is most commonly performed between the 10th week and 12th week of pregnancy and involves the insertion of a soft plastic into the vagina to obtain cells.

Correct Answer
verified

Correct Answer
verified

The pedigree below shows the segregation of an autosomal recessive trait. If III-3 and III-4 marry and have a child, what is the probability that this child will show the trait?

Correct Answer
verified

A trait is caused by a rare recessive autosomal allele with full penetrance. Practically all individuals with the trait result from matings between normal individuals. What would be the expected concordance values for monozygotic and dizygotic twins?

Correct Answer
verified

Correct Answer
verified

If the pedigree below is for an autosomal recessive characteristic, which individuals are definitely heterozygous?

Correct Answer
verified

Which of the following is NOT correctly identified as an advantage is using amniocentesis?

Correct Answer
verified

Correct Answer
verified

Correct Answer
Answered by ExamLex AI
(a) A direct-to-consumer genetic test is...
View Answer

A trait is caused by a rare dominant autosomal allele with full penetrance. Practically all individuals with the trait are heterozygous and result from matings between affected and normal individuals. What would be the expected concordance values for monozygotic and dizygotic twins?

Correct Answer
verified

Correct Answer
verified

Imagine that a human characteristic is determined by genotype only, with no environmental influence. Based on the amount of shared genetic information in MZ (monozygotic) and DZ (dizygotic) twins, what would you expect the concordance values to be in these two sets of twins?

Correct Answer
verified

Is it possible that the characteristic in the pedigree below could be X-linked dominant? If so, what is the genotype of each individual? If not, explain why not, giving specific genotypes. Use alleles B and b.

Correct Answer
verified

The pedigree below shows the segregation of an autosomal dominant trait. If IV-1 marries IV-5, what is the probability that their first child will be affected? Assume that the homozygous mutant genotype is viable and has the same phenotype as the heterozygote.

Correct Answer
verified

Exam 6: Pedigree Analysis, Applications, and Genetic Testing

Is it possible that the characteristic in the pedigree below could be X-linked recessive? If so, what is the genotype of each individual? If not, explain why not, giving specific genotypes. Use alleles A and a.

Correct AnswerverifiedShow Answer

This form of prenatal testing is most commonly performed between the 15th week and 18th week of pregnancy.

Correct AnswerverifiedShow Answer

In pedigree analysis, the proband is:

Correct AnswerverifiedShow Answer

Which statement is INCORRECT concerning an X-linked recessive trait in humans?

Correct AnswerverifiedShow Answer

Which of the following is NOT a characteristic of X-linked recessive traits in humans?

Correct AnswerverifiedShow Answer

If the phenotype followed in Pedigree 3 is X-linked recessive, then what is the genotype of II-2? Assume no new mutations and complete penetrance.

Correct AnswerverifiedShow Answer

This form of prenatal testing is most commonly performed between the 10th week and 12th week of pregnancy and involves the insertion of a soft plastic into the vagina to obtain cells.

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

The pedigree below shows the segregation of an autosomal recessive trait. If III-3 and III-4 marry and have a child, what is the probability that this child will show the trait?

Correct AnswerverifiedShow Answer

A trait is caused by a rare recessive autosomal allele with full penetrance. Practically all individuals with the trait result from matings between normal individuals. What would be the expected concordance values for monozygotic and dizygotic twins?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

If the pedigree below is for an autosomal recessive characteristic, which individuals are definitely heterozygous?

Correct AnswerverifiedShow Answer

Which of the following is NOT correctly identified as an advantage is using amniocentesis?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Correct AnswerAnswered by ExamLex AI(a) A direct-to-consumer genetic test is...View AnswerShow Answer

A trait is caused by a rare dominant autosomal allele with full penetrance. Practically all individuals with the trait are heterozygous and result from matings between affected and normal individuals. What would be the expected concordance values for monozygotic and dizygotic twins?

Correct AnswerverifiedShow Answer

Correct AnswerverifiedShow Answer

Imagine that a human characteristic is determined by genotype only, with no environmental influence. Based on the amount of shared genetic information in MZ (monozygotic) and DZ (dizygotic) twins, what would you expect the concordance values to be in these two sets of twins?

Correct AnswerverifiedShow Answer

Is it possible that the characteristic in the pedigree below could be X-linked dominant? If so, what is the genotype of each individual? If not, explain why not, giving specific genotypes. Use alleles B and b.

Correct AnswerverifiedShow Answer

The pedigree below shows the segregation of an autosomal dominant trait. If IV-1 marries IV-5, what is the probability that their first child will be affected? Assume that the homozygous mutant genotype is viable and has the same phenotype as the heterozygote.

Correct AnswerverifiedShow Answer

Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
Answered by ExamLex AI
(a) A direct-to-consumer genetic test is...
View Answer

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Correct Answer
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Correct Answer
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Correct Answer
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Correct Answer
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