Medical Genetics 4When a family with polygenic disease, if the patient's condition is more serious, the risk of re-birth offspring with this disease will be(5.0 Score )

A.Higher

B.Same with population prevalence

C.Lower

D.Difficult to estimate

2. To say that two alleles are in linkage disequilibrium implies that:(5.0 Score )

A.The alleles function together in the same pathway

B.One allele arose from the other by mutation

C.The alleles are so close that recombination never occurs between them

D.The two alleles are together in the same haplotype more often that predicted by chance

3. Association Studies:(5.0 Score )

A.Are used to map genes in multifactorial disorders

B.Include the transmission disequilibrium test (TDT)

C.Positive association studies should be replicated

D.Can give false positive results due to population stratification

E.Require closely matched control and patient groups

4. Types of nucleic acid hybridisation include the below EXCEPT(5.0 Score )

A.Southern blotting

B.Western blotting

C.Microarray

D.Northern blotting

E.DNA fingerprinting

5. When a family with polygenic disease, the more the number of patients, the risk of recurrence in their relatives will be(5.0 Score )

A.Higher

B.Same with population prevalence

C.Lower

D.Difficult to estimate

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6. After complete exome sequencing and analysis, an individual was found to have seven recessive mutations known to cause seven different diseases. The individual was heterozygous for all seven genes; the other alleles were normal. This means that(5.0 Score )

A.The individual has the seven genetic diseases

B.There is a high likelihood that at least some of the diseases will develop.

C.Because the mutations are recessive, none of the diseases is likely to develop

D.The diseases can be avoided only if a healthy lifestyle is adopted.

E.Whole genome sequencing is needed to confirm the results

7. A multifactorial trait occurs more often in females than males. A couple have an affected son. Which of the following is true regarding their risk of recurrence?(5.0 Score )

A.Recurrence is higher than if they had an affected daughter, and is most likely for a future son

B.Recurrence is higher than if they had an affected daughter, and is most likely for a future daughter.

C.Recurrence is higher than if they had an affected son , and is most likely for a future daughter

D.Recurrence is lower than if they had an affected daughter, and is most likely for a future daughter.

8. Linkage analysis is more difficult in multifactorial conditions than in single-gene disorders because:(5.0 Score )

A.Some multifactorial disorders are likely to have more than 1 etiology

B.The number of affected persons within in a family is likely to be fewer than for a single-gene disorder

C.The mode of inheritance is usually uncertain

D.Variants in more than 1 gene are likely to contribute to the disorder

E.Many multifactorial conditions have a late age of onset

F.All of above

9. The most accurate genetic diagnosis method is:(5.0 Score )

A.chromosomal karyotyping

B.Denaturing high-performance liquid chromatography (DHPLC)

C.Single strand conformation polymorphism (SSCP) analysis

D.DNA sequencing

E.Fluorescence in situ hybridization (FISH)

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10. Which of the following statements about a dominant genetic trait subject to genomic imprinting is NOT true?(5.0 Score )

A.Affected individuals will always inherit the mutation from either the mother or father, but not both.

B.The trait may appear to skip generations.

C.In a given family, only males or females will be affected.

D.Severity of the phenotype will be independent of sex of the affected individual.

E.Any of the above

11. Two parents with autosomal recessive albinism have a child who does not have albinism. This is best explained by:(5.0 Score )

A.Reversion of one of the mutant alleles to wild type

B.Misattributed paternity

C.Genetic heterogeneity

D.An incorrect diagnosis in one parent

E.pseudoautosomal inheritance

12. Pseudoautosomal inheritance is observed for which one of the following conditions?(5.0 Score )

A.Léri-Weill dyschondrosteosis

B.Duchenne muscular dystrophy

C.Glycerol kinase deficiency

D.Becker muscular dystrophy

E.Haemophilia A

13. Trinucleotide repeats that are associated with genetic disorders are located in which part of a (5.0 Score )

A.Introns

B.3' UTR

C.Exons

D.5' UTR

E.Any of the above

14. What mutational mechanism explains the fact that missense mutations in fibrillin-1 often cause a more severe Marfan syndrome phenotype than do truncating mutations in the same gene?(5.0 Score )

A.Missense mutations exhibit a loss of function

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B.Missense mutations are haploinsufficient

C.Missense mutations block the active site of the protein

D.Missense mutations are dominant negatives

E.Missense mutations alter the stability of the encoded Mrna

15. A candidate gene is likely to be a disease associated gene EXCEPT:(5.0 Score )

A.The pattern of expression of the gene is consistent with the phenotype

B.An animal model with a mutation in the orthologous gene has the same phenotype

C.Multiple different mutations cause the phenotype

D.A loss-of-function mutation causes the phenotype

E.It is a pseudogene

16. The population prevalence of cleft lip disease is 0.17%, heritability is 76%,the recurrence risk of the relatives of patients are(5.0 Score )

A.3%

B.2%

C.4%

D.5%

17. Jane is concerned about her risk of Huntington disease because her maternal grandfather died of the disease. Her mother is 45 year old and has not exhibited signs of the disease so Jane’s brother Mike tells her she’s worried for nothing. Which of the following properties of mutations in the Huntington disease gene suggests that Mike says might not be true?(5.0 Score )

A.X-linked inheritance

B.Age-dependent penetrance

C.High rate of mutation reversion

D.Incomplete penetrance

E.It is a sex-limited phenotype

18. In achondroplasia all heterozygotes show marked short stature. Inheritance is autosomal dominant. Parents of normal stature have 2 affected children. The most likely explantation for this is(5.0 Score )

A.germine mosaicism

B.reduced penetrance

C.variable expressivity

D.pseudodominant inheritance

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E.pseudoautosomal inheritance

19. Multiple studies of a given disorder among siblings have estimated the heritability of the disorder as equal to 0.85. What does this finding reveal about the cause of this disorder?(5.0 Score )

A.This disorder is likely caused by a single gene, with no environmental influences

B.The majority of the variance in the phenotype of this disease is caused by genetic influences

C.Environmental factors exert a greater influence over disease likelihhood than genetic factors

20. Which of the following statements is incorrect regarding the recurrence risk of multifactorial inherited disorders.(5.0 Score )

A.The risk gets higher when the degree of relationship increases

B.The risk gets higher when the number of patients in the family increase

C.The risk for their children gets higher when the patients are seriously affected

D.The risk gets higher when one or both parents are affected.

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Answers

Medical Genetics Test 3

Which of the following could produce an XY female?(5.0 Score )

A.Deletion of the Sry gene

B.Translocation of the Sry gene to the X chromosome during meiosis in the father

C.Point mutation in the Sry gene

D.All of the above

2. Each of the following chromosome abnormalities involves a 20 megabase region of the long arm of chromosome 5 (5q). Which abnormality is most likely to cause severe disease?(5.0 Score )

A.Duplication of the region

B.Deletion of the region

C.A balanced translocation involving the region (i.e., in the translocation carrier)

D.Pericentric inversion

3. Which of the following chromosomal aberrations can be of either sex:(5.0 Score )

A.XXY

B.XYY

C.trisomy 21

D.monosomic X

4. A person who has Klinefelter syndrome, Down syndrome, and cri-du-chat syndrome will have how many Barr bodies in each somatic-cell nucleus? (5.0 Score )

A.2

B.1

C.0

D.3

5. A woman with 14/21 translocation has aborted a male fetus after marriage, which of the following karyotype may be the male fetus?(5.0 Score )

A.46，XY,-14,+t(14q21q)

B.46，XY

C.46，XY,-21,+t(14q21q)

D.45，XY,-14,-21, +t(14q21q)

6. Which of the following generated 46, XY/47, XY, ＋21 chimeras(5.0 Score )

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A.Mitotic chromosome nondisjunction

B.Meiosis II chromosome nondisjunction

C.Meiosis I chromosome nondisjunction

D.Diandry

7. A family history of Down syndrome is reason to suspect(5.0 Score )

A.Chemical or drug sensitivity

B.Highly mutable genes

C.Nondisjunction

D.Inherited translocation

8. A cytogenetic term that refers to a mitotic cell that contains twice the normal number of chromosomes is:(5.0 Score )

A.endoreduplicated

B.polyploid

C.diploid

D.tetraploid

9. Human nucleolar organizer region is located in(5.0 Score )

A.Chromosome 4, 5

B.Chromosome 1, 2, 3

C.Chromosome 6-12

D.Chromosome 13, 14， 15， 21，22

10. 46,XX/45,X is(5.0 Score )

A.Chimeras with abnormal number of autosomal

B.Chimeras with abnormal structure of autosomal

C.Chimeras with abnormal number of sex chromosomes

D.Chimeras with abnormal structure of sex chromosomes

11. Currently, the most commonly used clinical technique of banding is(5.0 Score )

A.Q banding

B.C banding

C.G banding

D.T banding

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12. We observed three cell lines constituted by different chromosomes in an individual, this is known as:(5.0 Score )

A.Trisomy

B.Polyploid

C.Triploid

D.Chimera

13. The chromosome aberration that requires breaks in at least two nonhomologous chromosomes is(5.0 Score )

A.Inversion

B.Duplication

C.Deletion

D.Translocation

E.Centric fusion

14. Which of the following formed in tetraploid:(5.0 Score )

A.Digyny

B.Diandry

C.Endoreduplication

D.Unequal crossing over

15. If an eneuploid with a karyotype that is 2N +1 has 9 chromosomes, what is the normal haploid number of this species?(5.0 Score )

A.8

B.9

C.10

D.7

E.6

16. Basis of chromosomal aberrations is?(5.0 Score )

A.Chromosome breakage

B.Chromosome replication

C.Sister chromatid exchange

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D.Chromosome non-disjunction

17. The most common karyotype of Turner syndrome is:(5.0 Score )

A.47，XYY

B.47，XXY

C.45，X

D.47，XXX

18. Which of the following is not true of Fragile X syndrome? (5.0 Score )

A.It can be diagnosed using a karyotype

B.It is associated with methylation

C.It is caused by a trinucleotide repeat expansion

D.It displays nearly 100% penetrance

19. The most common karyotype of Klinefelter syndrome is:(5.0 Score )

A.47，XYY

B.47，XXY

C.45，X

D.47，XXX

20. Which of the following techniques was mostly used to detect a trisomy?(5.0 Score )

A.Southern blotting

B.RFLP

C.FISH

D.PCR-SSCP

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Answers

1. Which of the following elements is not an essential part element for a clone vector?(5.0 Score )

A.cos site

B.select marker (a system for screen )

C.restriction site (clone site)

D.replicon

2. Griffith’s experiment injecting a mixture of dead and live bacteria into mice demonstrated that(5.0 Score )

A.a factor was capable of transforming one bacterial cell type to another.

B.mRNA of eukaryotes differs from mRNA of prokaryotes.

C.DNA is double-stranded.

D.bacteria can recover from heat treatment if live helper cells are present.

3. In most animals,mitochondrial DNA is inherited:(5.0 Score )

A.From the female parent only

B.Predominantly from the male parent

C.Equally from both parents

D.From the male parent only

4. What percent of the human genome codes for polypeptide?(5.0 Score )

A.25%

B.10%

C.1%

D.40%

5. Mutations are(5.0 Score )

A.caused by faulty transcription of the genetic code

B.heritable changes in genetic information

C.caused by genetic recombination

D.usually, but not always, beneficial to the development of the individuals in which they occur

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6. What proportion of the total number of human genes is thought to be alternatively spliced?(5.0 Score )

A.45%

B.24%

C.60%

D.72%

7. The X-ray diffraction data obtained by Rosalind Franklin suggested(5.0 Score )

A.DNA is a left-handed helix

B.purines are hydrogen bonded to pyrimidines

C.DNA is a helix with a pattern that repeats every 3.4 nm

D.DNA is organized into nucleosomes

8. Who won the Nobel Prize for His (their) contributions to PCR technique?(5.0 Score )

A.Sanger F

B.Robert R and Sharp P

C.Southern E

D.Mullis K

E.Fire AZ and Mello CC

9. Ultraviolet light usually causes mutations by a mechanism involving(5.0 Score )

A.deletion of DNA segments

B.light-induced change of thymine to alkylated guanine

C.induction of thymine dimers and their persistence or imperfect repair

D.inversion of DNA segments

E.one-strand breakage in DNA

F.all of the above

10. Which of the following techniques was not used to detect an unknown mutations?(5.0 Score )

A.DGGE

B.ASO

C.SSCP

D.DNA sequencing

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11. Suppose you want to clone a human DNA fragment of 500kb, which of the following vectors do you need?(5.0 Score )

A.plasmid

B.cosmid

C.λ phage

D.YAC

12. The hybridization, which detects the specific RNA fragment, is called(5.0 Score )

A.Western Blot

B.Southern Blot

C.Northern Blot

D.Dot Blot

13. In a particular eukaryotic chromosome(5.0 Score )

A.heterochromatin is active, but euchromatin is inactive

B.heterochromatin and euchromatin are regions where genes make functional gene products (that is, where they are active)

C.heterochromatin is inactive, but euchromatin is active

D.both heterochromatin and euchromatin are inactive

14. A child from Nigeria is evaluated for developmental delay. His coloring seems much lighter than that of his family background, and his physician orders a blood amino acid test that demonstrates elevated phenylalanine. A special low phenylalanine formula is begun (Lofenelac) as treatment for phenylketonuria, but the parents refuse to come in for follow-up appointments. A public health evaluation reports that the child is failing to thrive despite apparent adherence to the diet by his parents. The symptoms of decreased skin pigment and later failure to thrive in this child are most likely related to which of the following?(5.0 Score )

A.Deficiency of tyrosine and melanin

B.Deficiency of alanine

C.Deficiency of tryptophan and niacin

D.Deficiency of leucine and isoleucine

E.Deficiency of phenylalanine

15. Ryan is diagnosed with HbH disease. This is likely caused by the deletion of how many of the alpha globingenes?(5.0 Score )

A.4

B.2

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C.3

D.1

E.5

16. A single nucleotide change in the gene for beta globin substitutes the amino acid valine for glutamic acid at the sixth position. This change affects the solubility of the resulting protein under certain conditions. What is the corresponding disorder?(5.0 Score )

A.Hydrops fetalis

B.Delta beta thalassemia

C.hereditary persistence of fetal hemoglobin

D.Cooley anemia

E.Sickle cell disease

17. Gene frequency is especially high among Ashkenazi Jews:(5.0 Score )

A.Marfan syndrome

B.Cystic fibrosis

C.Sickle cell disease

D.Tay-Sachs disease

E.Osteogenesis imperfecta

18. Which enzyme is most likely deficient in individuals with a mucopolysaccharidosis disorder?(5.0 Score )

A.Lysosomal enzymes involved in macromolecule degradation

B.An enzyme in the urea cycle leading to hyperammonemia

C.Liver enzymes necessary to degrade glycogen to release glucose

D.Enzymes that cleave sphingolipids

E.An enzyme necessary for the metabolism of monosacchrides such as fructose

19. Which gene is most likely to be expressed under the following conditions?(5.0 Score )

A.a gene which is methylated

B.a gene in a DNase hypersensitive site

C.a gene located in heterochromatin

D.a pesudogene

20. Increased resistance to malaria is seen in persons with hemoglobin AS, where A is the normal allele and S is the allele for sickle hemoglobin. Which of the following terms applies to this situation?(5.0 Score )

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A.Genetic drift

B.Heterozygote advantage

C.Founder effect

D.Fitness

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