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
In humans, the dominance relationship between the A and B alleles of the ABO blood group gene is an example of
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
An environmentally caused trait that appears to be inherited is called a (an)
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|
A woman who carries the CF gene and her homozygous normal husband have a child with CF. How can this occurrence be explained?
|D)||none of the above, infidelity is the only plausible explanation|
A____ is a group of genes or DNA sequences that are inherited together on the same chromosome.
Progeny that exhibit a mixing of maternal and paternal alleles on a single chromosome are
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.|
Only ____ transmit mitochondrial genes. Many mitochondrial disorders are ____, with mitochondria in a cell harboring different alleles.
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|
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?
|D)||all could be the father|
Alleles that are both expressed in a heterozygote are
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|
Some people with polydactyly have an extra toe; others have an extra finger. This situation is an example of a trait that is
|C)||both a and b.|
|D)||neither a nor b.|
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.
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|
Diseases resulting from mutations in mitochondrial genes affect
|C)||both a and b.|
|D)||neither a nor b.|
Consider the cross AAbb x aaBB. The alleles in the resulting dihybrid are in
|D)||none of the above.|
Given the gene sequence ABCDE, crossing over should occur most frequently between
|A)||A - B.|
|B)||A - C.|
|C)||A - D.|
|D)||A - E.|
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 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?
|C)||neither, they are incompletely dominant|
|D)||neither, they are codominant|
Consider the cross AaBb x AaBb. If the alleles for both genes exhibit incomplete dominance, what phenotypic ratio is expected in the resulting offspring?
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 phenotype is associated with a chromosomal aberration with
|D)||it is not possible to link genes to chromosomes.|