Genetics and Genomics MCQ Part 1 Flashcards
- A person with two or more different cell lines originating from a single zygote is called a:
a. Syndrome
b. Chimera (=of two different zygotes)
c. Pleiotropy
d. Mosaic
e. Heterozygote
d. Mosaic
- A cystic fibrosis mutation screen of an affected child reveals that he carries the Delta F508 mutation on one chromosome and the G551D mutation on the other chromosome. Which of the following terms best describes his situation?
a. Allelic heterogeneity
b. Complex heterozygosity (pete)
c. Locus heterogeneity
d. Lyonization
e. Pleiotropy
b. Complex heterozygosity (pete)
- Myotonic dystrophy may show increasing severity and earlier age of onset in successive generations. This phenomenon is known as:
a. Compound heterozygosity
b. Incomplete penetrance
c. Anticipation
d. Variable expressivity
e. Locus heterogeneity
c. Anticipation
- In people with sickle cell disease the red blood cells breakdown, clump, and clog the blood vessels. The broken cells accumulate in the spleen.
Among other things this leads to physical weakness, heart failure, pain, brain damage and spleen damage.
Affected individuals become paralyzed and can develop rheumatism, pneumonia and other diseases and kidney failure. This is an example of:
a. The polygenic nature of sickle cell disease
b. The pleiotropic effects of the sickle cell allele
c. An interaction between the sickle cell allele and proteolytic enzyme gene
d. Infectious organisms acting on the sickle cell allele
e. Side effects of the drugs used to cure sickle-cell disease
b. The pleiotropic effects of the sickle cell allele
- In a population expressing five different alleles for a particular gene, how many alleles may be present in each diploid organism in the population?
a. One
b. Two (One maternal + one paternal)
c. Three
d. Four
e. Five
b. Two (One maternal + one paternal)
- Polyploidy refers to:
a. Extra copies of a gene adjacent to each other on a chromosome
b. An individual with complete extra sets of chromosomes
c. A chromosome which has replicated but not divided
d. Several duplications of a gene adjacent to each other
e. An individual with extra copies of a chromosome
b. An individual with complete extra sets of chromosomes
- Pleiotropy refers to:
a. Multiple alleles each having partial control of one trait
b. The control of more than one trait by a single allele
c. Multiple alleles having co-dominant control of a trait
d. The tendency for alleles on the same chromosome to be inherited together
e. Multiple genes having control of one trait
b. The control of more than one trait by a single allele
- Duchenne muscular dystrophy and Becker muscular dystrophy have-different phenotypes but they result from mutations in the same gene. This is an example of:
a. Loss of heterozygosity
b. Locus heterogeneity
c. Variable expressivity
d. Compound heterozygosity
e. Allelic heterogeneity
Locus heterogeneity refers to mutations at different genetic loci (genes) that can cause the same or a similar phenotype. This situation fits the definition perfectly, since mutations at either of two loci on the X chromosome can both cause the hemophiliac phenotype.
- Polydactyly (extra finger) is a dominant trait in humans. A person who has polydactyly has parents who do not have polydactyly, and a maternal grandfather who does have polydactyly. What is the most likely explanation for this?
a. Codominance
b. Incomplete dominance
c. All environmental effect
d. Variable expressivity
e. Incomplete penetrance
e. Incomplete penetrance
- Which of the following defines the pseudoautosomal region?
a. Regions of the X and Y chromosomes that don’t recombine during meiosis
b. Homologous regions of the X and Y chromosomes
c. Hemizygous regions of the X and Y chromosomes
d. Heterozygous regions of autosomal chromosomes (=feil)
e. Homozygous regions of autosomal chromosomes
b. Homologous regions of the X and Y chromosomes
(inherited just like autosomal genes but are on X and Chromosome)
- Hemophilia A and hemophilia B have nearly identical phenotypes, but they result from a mutation in different genes on the X chromosome. This is an example of:
a. Allelic heterogeneity
b. Locus heterogeneity
c. Variable expressivity
d. Complex heterozygosity
e. Double heterozygosity
b. Locus heterogeneity
- What is true for the chromosome?
a. The DNA sequence of the two sister chromatids are identical
b. The DNA sequence of the two sister chromatids are similar the same
c. One of the sister chromatids of a chromosome is of maternal and the other is of paternal origin
d. The two sister chromatids are bound by kinetochore region (FEIL)
e. The DNA sequence of the two sister chromatids is different
a. The DNA sequence of the two sister chromatids are identical
- If you examine a pedigree showing the transmission pattern of mitochondrial gene mutation, which of the following states would be FALSE?
a. Mothers pass the gene to all offspring
b. Fathers do not transmit the gene
c. Only females will express the trait
d. Mothers pass the gene to all daughters
e. Mothers pass the gene to all sons
c. Only females will express the trait
(females and males can express the trait but only females can pass on the gene)
- What is it: The same genetic variations or genotype combinations simultaneously affect more than one phenotype trait?
a. Genetic heterogeneity
b. Complete penetrance
c. Pleiotropy
d. Expressivity
e. Phenocopy
c. Pleiotropy
- Huntington’s disease is an example of a genetic disorder caused by
a. Homozygous recessive alleles
b. A late acting recessive allele
c. A late acting dominant allele
d. A non-lethal dominant allele
e. Multiple alleles
c. A late acting dominant allele
- An interstitial deletion of paternal chromosome subregion 15q11-q13 results Prader- Willi syndrome (PWS). The deletion of the same subregion of maternal chromosome results another disease Angelman syndrome. The reason for this is:
a. Genomic imprinting
b. Non-mendelian inheritance
c. Mitochondrial inheritance
d. Nuclear inheritance
e. Variable expressivity
a. Genomic imprinting
- A genetic defect in humans results in the absence of sweat glands in the skin.
Some men have this defect all over their bodies, but in women it is usually expressed in a peculiar way.
A woman with this defect typically has small patches of skin with sweat glands and other patches where sweat glands are lacking.
This pattern suggests the phenotypic effect of:
a. Chromosome mutation
b. Gene mutation
c. Chromosome inactivation
d. RNA splicing
e. Chimerism
c. Chromosome inactivation
- Which one of these is caused by repeats of base triplets rather than a whole chromosome?
a. Down syndrome
b. Edward Syndrome
c. Klinefelter syndrome
d. Fragile-X syndrome
e. Turner syndrome
d. Fragile-X syndrome
- DNA fingerprinting is possible because:
a. Individuals, except identical (monozygotic) twins, are genetically unique
b. Different restriction enzymes is needed to cut different person’s DNA
c. Each person’s DNA uses different types of bases
d. Individuals are grown up in different environment
e. Each person has a unique set of genes
e. Each person has a unique set of genes
- During anaphase II (meiosis II)
a. Homologues separate and migrate towards opposite poles
b. Sister chromatids separate and migrate towards opposite poles
c. Nuclei reform
d. Chromosomes line up in the equator of the cell
e. The cells are diploid
b. Sister chromatids separate and migrate towards opposite poles
- In meiosis I anaphase:
a. Sister chromatids move toward opposite poles
b. Homologous chromosomes move toward opposite poles
c. Sister chromatids move toward the same poles
d. Homologous chromosomes move toward the same pole
e. Homologous chromosomes move randomly toward either pole
e. Homologous chromosomes move randomly toward either pole
- How can archeologist obtain enough DNA from unearthed human bones?
a. Subject the DNA to electrophoresis
b. Use a nucleic acid probe
c. Subject the specimen to Northern blot
d. Use polymerase chain reaction
e. Subject DNA to restriction enzyme
d. Use polymerase chain reaction
- What is it: severity of the illness can often vary in the affected persons even suffering from the very same variant?
a. Complete penetrance
b. Genetic heterogeneity
c. Phenocopy
d. Expressivity
e. Pleiotropy
d. Expressivity
- In a group of 100 women with the genotype for widow’s peak in the hairline, only 87 actually exhibited the trait. This is an example of:
a. Reduced penetrance
b. Anticipation
c. Heterogeneity
d. Pleiotropy
e. Variable expressivity
a. Reduced penetrance