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WorksheetsInheritance
Total questions: 20
Worksheet time: 2hrs 34mins
Albinism is a recessive trait. A man and woman both show normal pigmentation, but both have one parent who has albinism (without melanin pigmentation). What is the probability that their first child will have albinism?
0
1/2
1/4
1
Mendel crossed yellow-seeded and green-seeded pea plants and then allowed the offspring to self-pollinate to produce an F2 generation. The results were as follows: 6,022 yellow and 2,001 green (8,023 total). Which of the following statements correctly describes the relationship of the allele for green seeds to the allele for yellow seeds?
The green allele is dominant to the yellow allele.
The two alleles exhibit incomplete dominance.
The green allele is recessive to the yellow allele.
The two alleles are codominant.
Gray seed color in peas is dominant to white. Assume that Mendel conducted a series of experiments where plants with gray seeds were crossed among themselves, and the following progeny were produced: 302 gray and 98 white. What is the most probable genotype of each parent?
GG × gg
Gg × Gg
GG × Gg
gg × Gg
Black fur in mice (B) is dominant to brown fur (b). Short tails (T) are dominant to long tails(t). What fraction of the progeny of crosses BbTt × BBtt will be expected to have black fur and long tails?
1/16
3/8
1/2
9/16
Which of the following statements best describes the addition rule of probability?
the probability that two or more independent events will occur simultaneously
the probability that either one of two independent events will occur
the probability of producing two or more heterozygous offspring
the likelihood that a trait is due to two or more meiotic events
In cattle, roan coat color (mixed red and white hairs) occurs in the heterozygous (RW) offspring of red (RR) and white (WW) homozygotes. Which of the following crosses would produce offspring in the ratio of 1 red:2 roan:1 white?
red × white
roan × roan
white × roan
red × roan
Which of the following inheritance patterns describes the ability of a single allele to have multiple phenotypic effects?
incomplete dominance
multiple alleles
pleiotropy
epistasis
Which of the following phenotypes is an example of polygenic inheritance?
the ABO blood group in humans
pink flowers in snapdragons
skin pigmentation in humans
white and purple flower color in peas
Which of the following scenarios describes an example of epistasis?
Recessive genotypes for each of two genes (aabb) results in an albino corn snake.
In rabbits and many other mammals, one genotype (ee) prevents any fur color from
developing
In Drosophila (fruit flies), white eyes can be due to an X-linked gene or to a combination of other genes.
In cacti, there are several genes for the type of spines.
Gene S controls the sharpness of spines in a type of cactus. Cacti with the dominant allele, S,
have sharp spines, whereas homozygous recessive ss cacti have dull spines. At the same time, a
second gene, N, determines whether or not cactuses have spines. Homozygous recessive nn
cactuses have no spines at all. A cross between a true-breeding sharp-spined cactus and a
spineless cactus would produce ________.
all sharp-spined progeny
50% sharp-spined, 50% dull-spined progeny
25% sharp-spined, 50% dull-spined, 25% spineless progeny
It is impossible to determine the phenotypes of the progeny.
In human blood types, Rh positive is a trait that shows simple dominance over Rh negative. A woman who has blood type A positive has a daughter who is type O positive and a son who is type B negative. Which of the following phenotypes is possible for the father?
A negative
O negative
B positive
AB negative
Marfan syndrome in humans is caused by an abnormality of the connective tissue protein
fibrillin. Patients are usually very tall and thin, with long spindly fingers, curvature of the spine,
sometimes weakened arterial walls, and sometimes eye problems, such as lens dislocation.
Which of the following would you conclude about Marfan syndrome from this information?
It is recessive.
It is dominant.
It is pleiotropic.
It is epistatic.
One of two major forms of a human condition called neurofibromatosis (NF1) is inherited as a dominant gene, although it may range from mildly to very severely expressed. Which of the following is the best explanation for why a young, affected child is the first in her family to be diagnosed?
The mother carries the gene but does not express it.
One of the parents has a mild expression of the gene.
The condition skipped a generation in the family.
The child has one more chromosome than either of the parents.
Which of the following statements is a correct explanation for the observation that all offspring exhibit a phenotype for a particular trait that appears to be a blend of the two parental varieties?
Neither of the parental genes is dominant over the other.
The genes for the trait are dominant in both of the parents.
The genes are linked and do not separate during meiosis.
The genes for the trait are recessive in both of the parents.
Why are males more often affected by sex-linked traits than females?
Male hormones such as testosterone often alter the effects of mutations on the X
chromosome.
Female hormones such as estrogen often compensate for the effects of mutations on the X
chromosome.
X chromosomes in males generally have more mutations than X chromosomes in females.
Males are hemizygous for the X chromosome.
Which of the following statements correctly describes the meaning of the chromosome theory of inheritance as expressed in the early 20th century?
Individuals inherit particular chromosomes attached to genes.
Mendelian genes are at specific loci on the chromosome and, in turn, segregate during
meiosis.
No more than a single pair of chromosomes can be found in a healthy normal cell.
Natural selection acts on certain chromosome combinations rather than on genes.
Duchenne muscular dystrophy is a serious condition caused by a recessive allele of a gene on the human X chromosome. The patients have muscles that weaken over time because they have absent or decreased dystrophin, a muscle protein. They rarely live past their 20s. How likely is it for a woman to have this condition?
Women can never have this condition.
One-fourth of the daughters of an affected man would have this condition.
One-half of the daughters of an affected father and a carrier mother could have this condition.
Only if a woman is XXX could she have this condition.
Which of the following individuals will inherit an X-linked allele from a man who carries it?
all of his daughters
half of his daughters
all of his sons
all of his children
One possible result of chromosomal breakage is for a fragment to join a nonhomologous chromosome. What is this type of chromosomal alteration called?
deletion
inversion
translocation
duplication
Of the following human aneuploidies, which is the one that generally has the most severe impact on the health of the individual?
47, trisomy 21
47, XXY
47, XXX
45, X
