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1 | |
In familial hypercholesterolemia, individuals homozygous for the allele causing the disorder completely lack receptors on liver cells that take up cholesterol from the blood stream. Heterozygotes have one-half the number of receptors while individuals homozygous for the normal allele are phenotypically normal. This is an example of |
| | A) | complete dominance. |
| | B) | codominance. |
| | C) | incomplete dominance. |
| | D) | epistasis. |
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2 | |
In humans, the dominance relationship between the A and B alleles of the ABO blood group gene is an example of |
| | A) | complete dominance. |
| | B) | incomplete dominance. |
| | C) | codominance. |
| | D) | epistasis. |
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3 | |
The relationship of the I and H genes affects the expression of the ABO blood type in the following ways: genotype HH or Hh, AB produces blood type AB while genotype hh, AB produces blood type O. This is an example of |
| | A) | complete dominance. |
| | B) | codominance. |
| | C) | incomplete dominance. |
| | D) | epistasis. |
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4 | |
An environmentally caused trait that appears to be inherited is called a (an) |
| | A) | pleiotropic gene. |
| | B) | penetrant gene. |
| | C) | expressed gene. |
| | D) | phenocopy. |
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5 | |
Two albino individuals marry and start a family. Their first child is normal in pigmentation. Is infidelity suspected and why/why not? |
| | A) | yes, albinism is recessive and neither parent carries a pigment gene |
| | B) | no, albinism is dominant therefore at least one of the parents is a carrier |
| | C) | no, each parent has a different allele causing his or her albinism (genetic heterogeneity) |
| | D) | cannot be determined from the limited information given |
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6 | |
A woman who carries the CF gene and her homozygous normal husband have a child with CF. How can this occurrence be explained? |
| | A) | heteroplasmy |
| | B) | uniparental disomy |
| | C) | genomic imprinting |
| | D) | none of the above, infidelity is the only plausible explanation |
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7 | |
A____ is a group of genes or DNA sequences that are inherited together on the same chromosome. |
| | A) | haplotype |
| | B) | genotype |
| | C) | heteroplast |
| | D) | phenotype |
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8 | |
Progeny that exhibit a mixing of maternal and paternal alleles on a single chromosome are |
| | A) | parentals. |
| | B) | recombinants. |
| | C) | haplotypes. |
| | D) | mixed groups. |
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9 | |
If the percent recombination between A and B is 12, between A and C is 4, and between B and C is 8, then the order of the genes on the chromosome is |
| | A) | A - B - C. |
| | B) | B - A - C. |
| | C) | A - C - B. |
| | D) | C - B - A. |
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10 | |
Only ____ transmit mitochondrial genes. Many mitochondrial disorders are ____, with mitochondria in a cell harboring different alleles. |
| | A) | males, heteroplasmic |
| | B) | males, heteromorphic |
| | C) | females, heteromorphic |
| | D) | females, heteroplasmic |
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11 | |
Two Mexican hairless dogs are crossed. What ratio of hairy : hairless dogs is expected in the offspring generation? |
| | A) | 3 hairless : 1 hairy |
| | B) | 3 hairy : 1 hairless |
| | C) | 2 hairless : 1 hairy |
| | D) | cannot be predicted |
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12 | |
A woman with type A blood has a child with type A blood. Which of the following men could not be the father of this child? |
| | A) | A |
| | B) | B |
| | C) | AB |
| | D) | all could be the father |
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13 | |
Alleles that are both expressed in a heterozygote are |
| | A) | completely dominant. |
| | B) | codominant. |
| | C) | incompletely dominant. |
| | D) | epistatic. |
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14 | |
The Bombay phenotype is a result of ____ interacting genes and is an example of ____. |
| | A) | 2, complete dominance |
| | B) | 2, incomplete dominance |
| | C) | 3, incomplete dominance |
| | D) | 2, epistasis |
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15 | |
Some people with polydactyly have an extra toe; others have an extra finger. This situation is an example of a trait that is |
| | A) | incompletely penetrant. |
| | B) | variably expressed. |
| | C) | both a and b. |
| | D) | neither a nor b. |
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16 | |
Marfan Syndrome, a dominant single-gene defect, is characterized by lens dislocation, long limbs, spindly fingers, a caved-in chest, and a weakened aorta. This is an example of a (an) ____ trait. |
| | A) | multifactorial |
| | B) | pleiotropic |
| | C) | incompletely dominant |
| | D) | phenocopy |
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17 | |
If you examine a pedigree showing the transmission pattern of a mitochondrial gene mutation, which of the following statements 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) | all of the above statements are true |
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18 | |
Diseases resulting from mutations in mitochondrial genes affect |
| | A) | protein synthesis. |
| | B) | energy acquisition. |
| | C) | both a and b. |
| | D) | neither a nor b. |
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19 | |
Consider the cross AAbb x aaBB. The alleles in the resulting dihybrid are in |
| | A) | coupling. |
| | B) | repulsion. |
| | C) | heteroplasmy. |
| | D) | none of the above. |
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20 | |
Given the gene sequence ABCDE, crossing over should occur most frequently between |
| | A) | A - B. |
| | B) | A - C. |
| | C) | A - D. |
| | D) | A - E. |
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21 | |
Consider two recessive alleles (a and b) in humans. Given the following data, determine the distance between the two genes (in map units): AaBb = 206; Aabb = 704; aaBb = 736; aabb = 254. |
| | A) | 12.7 |
| | B) | 1 |
| | C) | 24.2 |
| | D) | 28 |
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22 | |
A geneticist crosses a plant with red flowers to a plant with white flowers. The offspring include plants with red flowers (1/4), pink flowers (1/2), and white flowers (1/4). Which allele is dominant? |
| | A) | red |
| | B) | white |
| | C) | neither, they are incompletely dominant |
| | D) | neither, they are codominant |
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23 | |
Consider the cross AaBb x AaBb. If the alleles for both genes exhibit incomplete dominance, what phenotypic ratio is expected in the resulting offspring? |
| | A) | 1:1:1:1 |
| | B) | 9:3:3:1 |
| | C) | 3:6:3:1:2:1 |
| | D) | 1:2:1:2:4:2:1:2:1 |
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24 | |
Consider the cross AaBb x AaBb. If trait A exhibits complete dominance and trait B exhibits codomiance, what phenotypic ratio is expected in the offspring? |
| | A) | 1:1:1:1 |
| | B) | 9:3:3:1 |
| | C) | 3:6:3:1:2:1 |
| | D) | 1:2:1:2:4:2:1:2:1 |
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25 | |
A phenotype is associated with a chromosomal aberration with |
| | A) | linkage maps. |
| | B) | haplotypes. |
| | C) | cytogenetics. |
| | D) | it is not possible to link genes to chromosomes. |
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