genetic ch 5
Consider an organism that is heterozygous for the genes Y and Z. If the two recessive alleles are on one chromosome, the genes are in _____. A) cis B) trans C) the parental configuration D) the recombinant configuration
a
Alleles that are both expressed in a heterozygote are _____. A) completely dominant B) codominant C) incompletely dominant D) epistatic
b
____ describes an allele combination in which the heterozygous phenotype is distinct from, and is not an intermediate between, those of the two homozygotes (for example, AB blood type). Both alleles are equally expressed. A) Complete dominance B) Codominance C) Incomplete dominance D) Epistasis
b
A field called ____ matches phenotypes to chromosomal variants. A) linkage maps B) haplotypes C) cytogenetics D) genome wide association studies
c
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
c
Diseases resulting from mutations in mitochondrial genes affect _____. A) mitochondrial protein synthesis B) cellular energy reactions C) both a and b D) neither a nor b
c
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
c
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
c
Some people with polydactyly do not have any extra digits; some have an extra toe, while others have an extra finger. This situation is an example of a trait that is: A) incompletely penetrant. B) variably expressive. C) both a and b D) neither a nor b
c
The term that is used to describe the severity or extent of a phenotype in an individual is called _____. A) pleiotropy B) penetrance C) expressivity D) epistasis
c
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
c
When a teratogen causes a birth defect that is similar to a genetic disorder, this is referred to as _____. A) genetic heterogeneity B) pleiotropy C) a phenocopy D) epistasis
c
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
d
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
d
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
a
The term _____ refers to the condition in which DNA bases in the mitochondrial genome differ within an individual. A) Heteroplasmy B) Epistasis C) Genetic Heterogeneity D) Pleiotropy
a
You are studying a degenerative condition that appears to be passed on only from the mother of the family. Affected fathers do not pass the trait to the offspring. This suggests that the trait might be _____. A) mitochondrial B) lethal C) epistatic D) incompletely dominant
a
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(n) ____ trait. A) multifactorial B) pleiotropic C) incompletely dominant D) phenocopy
b
Progeny that exhibit a mixing of maternal and paternal alleles on a single chromosome are _____. A) parentals B) recombinants C) haplotypes D) mixed groups
b
The gene A exhibits incomplete dominance. What can we expect about the offspring from the mating of two heterozygotes? A) a 3:1 phenotypic ratio B) phenotypic ratios that match the genotypic ratios C) a 2:1 phenotypic ratio D) an equal number of homozygous dominant phenotypes as intermediate phenotypes
b
Which of the following diseases is an example of a pleiotropic condition? A) cystic fibrosis B) porphyria variegata C) Leber congenital amaurosis D) familial hypercholesterolemia
b
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.
c
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
c
Which of the following blood types is not possible from two parents with type A blood? A) A B) O C) B D) All of the above are possible
c
____ allele combinations cause offspring to die early in development. A) Epistatic B) Variably expressive C) Lethal D) Codominant
c
____ describes an allele combination in which the heterozygous phenotype is intermediate between those of the two homozygotes (for example, pink flowers are intermediate between red flowers and white flowers). The dominant allele does not completely mask the recessive allele. A) Complete dominance B) Codominance C) Incomplete dominance D) Epistasis
c
A man who is homozygous for type A blood has a child with a woman who is homozygous for type B blood. What is the probability that this child will have type AB blood? A) 0%. B) 25% C) 50% D) 100%
d
All of the following are features of mitochondrial DNA EXCEPT: A) mutates faster than DNA in the nucleus. B) maternal inheritance. C) no crossing over. D) one copy per mitochondrion.
d
An environmentally caused trait that appears to be inherited is called a(n) _____. A) pleiotropic gene B) penetrant gene C) expressed gene D) phenocopy
d
Given the gene sequence ABCDE, crossing over should occur most frequently between _____. A) A - B B) A - C C) A - D D) A - E
d
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
d
The first genetic linkage map was constructed in what organism? A) bacteria B) yeast C) peas D) fruit flies
d
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
d
____ describe(s) how several allele variants for a particular gene can exist in a given population. For example, for hair color there can be black, brown, red, blond hair, etc. A) Complete dominance B) Codominance C) Incomplete dominance D) Multiple alleles
d
