Deck 13: Observing Patterns in Inherited Traits

Question 1

The illustration above shows the F₂ phenotypes from a monohybrid cross in snapdragons.What type of inheritance produces such an outcome?

A) complete dominance
B) incomplete dominance
C) multiple alleles
D) continuous variation
E) epistasis

Answer 1

B

Question 2

The pea plant was an excellent choice for Mendel's experiments because

A) true-breeding varieties were available.
B) the plant can self-fertilize.
C) it can be cross-fertilized.
D) true-breeding varieties were available, and it can be cross-fertilized.
E) true-breeding varieties were available, the plant can self-fertilize, and it can be cross-fertilized.

Answer 2

E

Question 3

Which offspring in the illustration above are homozygous recessive for both traits?

A) A
B) B
C) C
D) D
E) none of these

Answer 3

D

Question 4

A gene that produces multiple effects is called

A) a multiple allele.
B) an autosome.
C) an epistatic gene.
D) a pleiotropic gene.
E) an incompletely dominant gene.

Question 5

For Mendel's explanation of inheritance to be correct,

A) the genes for the traits he studied have to be located on the same chromosome.
B) the combination of gametes at fertilization has to be due to chance.
C) genes cannot be transmitted independently of each other.
D) only diploid organisms demonstrate inheritance patterns.
E) none of these apply.

Question 6

An individual with a genetic makeup of aa BB is called

A) true-breeding.
B) recessive.
C) hybrid.
D) dihybrid.
E) heterozygous.

Question 7

The F₂ phenotypic ratio of 9:3:4 is a result of a cross involving

A) two genes expressing complete dominance.
B) a gene expressing dominance and another gene expressing codominance.
C) two genes expressing codominance.
D) epistasis, in which one gene modifies the expression of the other gene.
E) multiple alleles.

Question 8

The most accurate description of an organism with genotype AaBb is

A) homozygous dominant.
B) heterozygous.
C) heterozygous dominant.
D) homozygous recessive.
E) heterozygous recessive.

Question 9

Mendel's dihybrid crosses, but not his monohybrid crosses, show that

A) some genes are linked together.
B) the two alleles controlling a trait are divided equally among the gametes.
C) alleles for different traits are inherited independently.
D) one of the pair of alleles is dominant to the other.
E) the crossing of two different homozygous forms will not produce any offspring in the first generation that will look like either of the parents.

Question 10

The ABO blood types are controlled by

A) pleiotropy.
B) multiple alleles.
C) incomplete dominance.
D) codominance.
E) multiple alleles and codominance.

Question 11

The CFTR protein product is responsible for:

A) pumping chloride ions out of the cell.
B) pumping water out of the cell.
C) pumping chloride ions into the cell.
D) fighting off bacterial infections.
E) regulating gene expression.

Question 12

Multiple effects of a single gene is

A) expressivity.
B) penetrance.
C) codominance.
D) pleiotropy.
E) multiple alleles.

Question 13

Where would the CFTR gene not be heavily expressed?

A) Lungs.
B) Reproductive system.
C) Intestines.
D) Brain.
E) Skin.

Question 14

Which of the following is NOT TRUE of cystic fibrosis?

A) It produces sticky mucus.
B) It leads to increased bacterial lung infections.
C) The amino acid affected is phenylalanine.
D) It causes insufficient water to leave the cells.
E) All of these are true.

Question 15

Genes at one locus that affect the expression of genes at a different locus are said to be

A) epistatic.
B) linked.
C) codominant.
D) penetrant.
E) alleles.

Question 16

-Using the illustration above and the assumption that half of a plant's sperm and eggs are a and half are A, one can predict that the chance of sperm a meeting egg A at fertilization is

A) 1/2 * 1/2.
B) 25 percent.
C) one out of four.
D) 1/2.
E) all of these EXCEPT 1/2.

Question 17

In ____, a pair of nonidentical alleles affecting two phenotypes for a given trait are both expressed at the same time in heterozygotes.

A) pleiotropy
B) polygenic inheritance
C) complete dominance
D) codominance
E) a multiple allele system

Question 18

According to Mendel, what kinds of genes "disappear" in F₁ pea plants?

A) sex-linked
B) dominant
C) recessive
D) codominant
E) lethal

Question 19

A gene locus is

A) a recessive gene.
B) an unmatched allele.
C) a sex chromosome.
D) the location of an allele on a chromosome.
E) a dominant gene.

Question 20

Various forms of a single gene at a given locus is called

A) kinetochores.
B) alleles.
C) autosomes.
D) loci.
E) chromatids.

Question 21

Height, weight, and eye color are examples of phenotypes that illustrate all BUT

A) polygenic inheritance.
B) continuous variation.
C) pleiotropy.
D) the action of several gene pairs each with additive effects.
E) the cumulative effect of several gene products acting to determine phenotype.

Question 22

Which of the following is NOT a known effect in the expression of Marfan syndrome?

A) lanky, loose jointed skeleton
B) weakened blood vessels
C) calcium deposits in aorta
D) excessive absorption of oxygen causing the blood cells to swell
E) skin becomes inelastic

Question 23

Which of the following is FALSE about Marfan syndrome?

A) It results from an autosomal dominant mutation.
B) The affected gene produces a defective form of the protein fibrillin.
C) Connective tissues are weakened.
D) It affects one in ten thousand men and women.
E) None of these is false.

Question 24

Which of the following has been correlated with the ability of rats to cope with stress as adults?

A) A nurturing mother.
B) The number of siblings they have.
C) The temperature they are raised in.
D) The altitude they are born at.
E) All of these.

Question 25

Yarrow will not alter its phenotype in response to:

A) temperature.
B) soil conditions.
C) being produced by sexual versus asexual reproduction.
D) water conditions.
E) changing altitude.

Question 26

In the classic argument of 'nature vs.nurture', nature would most correspond with:

A) genes.
B) environment.
C) divine intervention.
D) environment and genes.
E) genes, environment, and genes.

Question 27

Which is easier to establish in a pure-breeding population, a dominant or a recessive gene?

Question 28

A graph of phenotypic variation similar to the illustration above strongly suggests

A) incomplete dominance.
B) codominance.
C) epistasis.
D) polygenic inheritance.
E) environmental effects on phenotype.

Question 29

Which of the following does not stimulate the production of males in water fleas?

A) spring.
B) warm water.
C) salty water.
D) high competition for resources.
E) crowding.

Question 30

Pleiotropic genes

A) act on secondary sexual characteristics.
B) influence more than one aspect of phenotype.
C) are additive.
D) produce lethal effects when homozygous.
E) are none of these.

Question 31

Tall (D) is dominant to dwarf (d).Give the F₂ genotypic and phenotypic ratios of a cross between a pure-breeding tall plant and a pure-breeding dwarf plant.

Question 32

If wire hair (W) is dominant to smooth hair (w), and you find a wire-haired puppy, how would you determine its genotype by a genetic breeding experiment? Give both the genotype and phenotype involved with the cross with the unknown.

Question 33

In a certain plant, when individuals with blue flowers are crossed with individuals with blue flowers, only blue flowers are produced.Plants with red flowers crossed with plants with red flowers sometimes produce only red flowers, although other times they produce either red or blue flowers.When plants with red flowers are crossed with plants with blue flowers, sometimes only red flowers are produced; other times either red or blue flowers are produced.Which gene is dominant?

Question 34

The role of environmental factors on gene expression is illustrated by

A) the varying plant height of genetically identical yarrow plants when grown at different elevations.
B) the flower color of hydrangeas grown in soils of differing pH.
C) the depression response that some persons make to very stressful situations.
D) the fur pattern of Himalayan rabbits.
E) all of these.

Question 35

Unexpected phenotypes can be the result of

A) altered metabolic pathways.
B) a gene mutating in different ways in different individuals.
C) an environmental effect during development.
D) a post-developmental environmental effect.
E) any of these.

Question 36

A bell-shaped curve of phenotypic variation is indicative of

A) incomplete dominance.
B) continuous variation.
C) multiple alleles.
D) epistasis.
E) environmental variables on phenotypes.

Question 37

Which of the following is FALSE about camptodactyly?

A) Not all individuals who inherit the allele do express the allele.
B) The condition affects the shape and mobility of fingers.
C) Some individuals have abnormal fingers on only one hand.
D) It is caused by a multiple allele system.
E) Individual differences in the expression of this gene may stem from a variety of causes.

Question 38

Which eye color has the gene combination to deposit the most melanin in the iris?

A) blue.
B) gray.
C) brown.
D) green.
E) all are the same.

Question 39

Which of the following can impact methylation patterns?

A) drugs.
B) exercise.
C) stress.
D) diet.
E) all of these.

Question 40

In which of the following does environment not play a role?

A) depression.
B) bipolar disorder.
C) schizophrenia.
D) depression and schizophrenia.
E) it plays a role in all these.

Question 41

In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color.The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p).A tall plant with purple flowers crossed with a dwarf plant with white flowers produces 1/2 tall with purple flowers and 1/2 tall with white flowers.What is the genotype of the parents?

Question 42

In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color.The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p).A tall plant with white flowers crossed with a dwarf plant with purple flowers produces all tall offspring with purple flowers.What is the genotype of the parents?

Question 43

In horses, black coat color is influenced by the dominant allele (B), and chestnut coat color is influenced by the recessive allele (b).Trotting gait is due to a dominant gene (T), pacing gait to the recessive allele (t).If a homozygous black trotter is crossed to a chestnut pacer,
(a)
what will be the appearance of the F₁ and F₂ generations?
(b)
which phenotype will be the most common?
(c)
which genotype will be the most common?
(d)
which of the potential offspring will be certain to breed true?

Question 44

If black fur color is controlled by a dominant allele (B) and brown by its recessive allele (b), give the genotypes of the parents and offspring of a cross of a black male with a brown female that produces 1/2 black offspring and 1/2 brown offspring.

Question 45

If long or round are homozygous forms of an incompletely dominant gene, and oval is the phenotype of the heterozygote, give the F₂ ratio of the cross between long and round (both genotype and phenotype).

Question 46

In horses, black coat color is influenced by the dominant allele (B), and chestnut coat color by the recessive allele (b).Trotting gait is due to a dominant gene (T), pacing gait to the recessive allele (t).What color horse would you use to find out the genotype of a black trotter? Give the genotype and phenotype.

Question 47

Assume that red plants crossed with white plants give rise to pink plants.Explain how to eliminate red plants if you start with two pinks.

Question 48

In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color.The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p).A tall plant with white flowers crossed with a dwarf plant with purple flowers produces 1/4 tall purple, 1/4 tall white, 1/4 dwarf purple, and 1/4 dwarf white.What is the genotype of the parents?

Question 49

In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color.The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p).A tall plant with purple flowers crossed with a dwarf plant with white flowers produces 1/4 tall purple, 1/4 tall white, 1/4 dwarf purple, and 1/4 dwarf white.What is the genotype of the parents?

Question 50

In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color.The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p).A tall purple crossed with a tall purple produces 3/4 tall purple and 1/4 tall white.What is the genotype of the parents?

Question 51

There are three alleles controlling the ABO blood types.I^A and I^B are codominant genes so that the combination I^AI^B produces the AB blood type.The third allele, I^O, is recessive to the other two alleles.Indicate which of these parents could produce the given child:
Parents
Child
Yes or No
(a)
A * AB
B
(b)
A * O
A
(c)
A * B
O
(d)
A * AB
O
(e)
A * AB
B
(f)
B * B
O
(g)
AB * AB
A

Question 52

In poultry, rose comb is controlled by a dominant allele, and its recessive allele controls single comb.
(a)
Give the genotype and phenotype produced from crossing a pure-breeding rose comb chicken with a pure-breeding single comb chicken.
(b)
Give the results of the backcross of the F₁ hybrid with both pure-breeding parents.

Question 53

A breeder of cattle has a herd of white cows and a roan bull.Hair color in this breed is controlled by an incompletely dominant gene.The two homozygous forms are either red or white, and the heterozygous is roan.
(a)
What colors of calves are expected and in what proportions?
(b)
Outline a procedure to develop an all-red herd.

Question 54

If 2 spot (S) is dominant to 4 spot (s), give the genotypes for the parents in the following crosses:
(a)
2 spot * 2 spot yields 2 spot and 4 spot
(b)
2 spot * 4 spot yields only 2 spot
(c)
2 spot * 4 spot yields 2 spot and 4 spot
(d)
2 spot * 2 spot yields only 2 spot
(e)
4 spot *4 spot yields only 4 spot

Question 55

In garden peas, one pair of alleles controls the height of the plant, and a second pair of alleles controls flower color.The allele for tall (D) is dominant to the allele for dwarf (d), and the allele for purple (P) is dominant to the allele for white (p).A tall plant with purple flowers crossed with a tall plant with white flowers produces 3/8 tall purple, 1/8 tall white, 3/8 dwarf purple, and 1/8 dwarf white.What is the genotype of the parents?

Question 56

In radishes, two incompletely dominant genes control color and shape.Red and white radishes are homozygous, whereas the hybrid is purple.Long and round are homozygous and, if crossed, will produce an oval hybrid.Give the F₂ genotypic and phenotypic ratio produced by crossing pure-breed red long radishes with white round varieties.

Question 57

The allele for albinism (c) is recessive to the allele for normal pigmentation (C).A normally pigmented woman whose father is an albino marries an albino man whose parents are normal.They have three children, two normal and one albino.Give the genotypes for each person listed.

Question 58

In a certain breed of chicken, an incomplete dominant gene controls color.The homozygous black, when crossed with the homozygous splashed-white, produces an intermediate gray color pattern referred to as blue.A second gene controls the shape of the comb.The dominant allele (R) produces rose, whereas the recessive allele (r) produces single.Give the F₁ and F₂ genotypic and phenotypic ratios of a cross between a pure-breeding black single and a pure-breeding splashed-white rose.

Question 59

In humans, normal skin pigmentation is influenced by a dominant gene (C), which allows pigmentation to develop.All individuals who are homozygous for the recessive allele (c) are unable to produce an enzyme needed for melanin formation and are therefore referred to as albino.Two normal parents produce an albino child.What are the chances that the next child will be an albino?

Question 60

Crosses between a yellow rat with a yellow rat always produce yellow.Crosses between a white rat with a white rat always produce white.The alleles affect the same aspect of coat color.The crosses of a white with a yellow produce a cream.What happens if you cross two creams?

Question 61

White fruit color in summer squash is influenced by a dominant allele W, whereas colored fruit must be ww.In the presence of ww, a dominant gene G results in yellow fruit, and if the individual had both recessive genes in the homozygous condition, it would be green.Give the F₂ phenotypic ratios resulting from a cross of a pure-breeding white of genotype WW GG with a green.

Question 62

In tomatoes, red (R) is dominant to yellow (r), tall (D) is dominant to dwarf (d), and smooth (H) is dominant to peach or hairy (h).
(a)
How many different genotypes are there in relationship to these three characteristics?
(b)
How many different phenotypes are there in relationship to these three characteristics?
(c)
How many different homozygous pure-breeding forms can be produced?

Question 63

In mice the allele for colored fur (C) is dominant to the allele for albinism (c).The allele for normal behavior (W) is dominant to that for waltzing movement (w).Give the probable genotypes of the parents if they produced the offspring listed after the following crosses:
(a)
colored normal * white waltzer produced 10 colored normal, 8 colored waltzers, 2 white waltzers, 11 white normal
(b)
colored normal * white normal produced 35 colored normal, 13 colored waltzers
(c)
colored normal * colored normal produced 37 colored normal, 14 colored waltzers, 9 white normal, and 5 white waltzers

Question 64

In cultivated stocks, the cross of a variety of white flower plants produced all red flowers in the F₁ generation, but the F₂ generation produced 87 red, 31 cream, and 39 white.Explain these results by giving the genotypes possible for each phenotype.

Question 65

In a certain variety of plants, a cross between a red-flowered plant and a white-flowered plant produced an all-red flower F₁.In the F₂ there were 140 red, 50 cream, and 65 white.
(a)
Offer an explanation for this F₂ ratio.
(b)
What ratio would be produced in a testcross of the F₁ hybrid?
(c)
What ratio would be produced if all the white F₂ plants were crossed among themselves?

Question 66

In the late 1920s, a mutation occurred in many silver fox farms around the world.The fox farms that sold expensive furs were proud of the quality of their furs, and each advertised that it had the best, purest breed of all the fox farms.The new mutations produced a "platinum" coat pattern that was commercially desirable, so the farms crossed them to get more.The results of their breeding experiments were as follows: (1) silver *silver >>> all silver offspring; (2) silver * platinum >>> equal numbers of silver and platinum; (3) platinum * platinum >>> two platinum for each silver offspring.Explain.

Question 67

In horses, there are four alleles at the A locus.Arranged in dominance sequence they are:
A (wild), a^b (bay), a^c (brown), a^d (black)
If you bred several bay mares whose sires were brown to a brown stallion whose sire was black, what are the genotypes of the parents; what type of offspring would be produced; and in what proportion?

Question 68

In rabbits, there are four alleles at the c locus.Arranged in dominance sequence they are:
C (agouti), c^ch(chinchilla), c^h(Himalayan), and c (albino)
(a)
Is it possible to cross two agouti rabbits and produce both chinchilla and Himalayan offspring?
(b)
Is it possible to cross two chinchillas and produce 1/2 chinchilla and 1/2 Himalayan?

Question 69

In poultry, the genes for rose comb (R) and pea comb (P) produce walnut whenever they occur together (R__ P__); single-combed individuals have the homozygous condition for both genes (rr pp).
(a)
Give the F₁ and F₂ phenotypic results of a cross of a pure-breeding rose comb (RR pp) with a pure-breeding pea comb (rr PP).
(b)
Give the phenotypic results of a cross of Rr Pp * rr Pp.
(c)
Give the phenotypic results of a cross of RR Pp * rr Pp.
(d)
Give the phenotypic results of a cross of Rr pp * rr Pp.
(e)
Give the phenotypic results of a cross of Rr Pp * rr pp.

Question 70

In summer squash, spherical-shaped fruit has been shown to be dominant to elongated fruit.On one occasion two different spherical varieties were crossed and produced all disk-shaped fruits.When these hybrid disk-shaped fruits were crossed, they produced 75 disk-shaped fruits, 48 spherical fruits, and 9 elongated fruits.Explain these results.

Question 71

If you were following the inheritance patterns of two different sets of multiple alleles located on different chromosomes, how many different possible gametes could be produced if locus 1 had five possible alleles and locus 2 had six alleles?

Question 72

In the garden pea, Mendel found that tall (D) green pods (G) and inflated pods (C) were dominant to their alleles, dwarf (d) yellow pods (g) and constricted pods (c).Given the following genotypes, determine the chances of producing the offspring shown.
(a)
DD Gg Cc * Dd Gg cc $\rightarrow$ DD gg Cc
(b)
DD Gg Cc* Dd Gg Cc $\rightarrow$ tall green pod, constricted pod
(c)
Dd Gg Cc * Dd GG cc $\rightarrow$ tall green pod, inflated pod
(d)
Dd Gg Cc * Dd Gg Cc $\rightarrow$ D__ G__ cc
(e)
Dd Gg Cc * Dd gg CC $\rightarrow$ D__ G__ C__
(f)
Dd gg cc * DD Gg cc F $\rightarrow$ tall green pod, inflated pod
(g)
Dd Gg Cc * Dd Gg Cc $\rightarrow$ Dd Gg Cc
(h)
Dd Gg Cc *Dd Gg Cc $\rightarrow$ dd gg cc

Question 73

There are nine coat colors known in foxes.If a red fox were crossed with a double-black fox, all the hybrids would be red above and black below in a pattern known as blended cross.If two blended crosses were mated, the F₂ ratio would be as follows: 1 red, 2 smoky red, 2 cross red, 4 blended cross, 1 standard silver, 2 substandard silver, 1 Alaskan silver, 2 sub-Alaskan silver, and 1 double black.
(a)
Using the letters A/a and B/b to serve as the genes for these animals, develop a genotype for each variety listed.
(b)
Two crosses will produce all blended-cross offspring.One is used above (red fox * double black); what is the other?
(c)
List the genotype and phenotype of all the pure-breeding foxes.
(d)
Give the genotypic and phenotypic ratio of a cross between two substandard silvers.
(e)
Give the genotype and phenotype of the offspring produced in a cross of a sub-Alaskan silver and a cross red.

Question 74

A cross of two Kerry horses always produces Kerry.A cross of a Kerry with a Dexter produces 1/2 and 1/2.Crosses of two Dexters produce two Dexters for every Kerry.Explain.

Question 75

In sweet peas, genes C and P are necessary for colored flowers.In the absence of either (__ pp or cc __) or both (cc pp), the flowers are white.What will be the color of the offspring of the crosses listed below and in what proportions?
(a)
Cc Pp * cc pp
(b)
Cc Pp *Cc Pp
(c)
Cc PP * Cc pp
(d)
Cc pp * cc Pp

Question 76

In sweet peas, genes C and P are necessary for colored flowers.In the absence of either (__ pp or cc __) or both (cc pp), the flowers are white.Give the probable genotype of a plant with colored flowers and a plant with white flowers that produced 38 plants with colored flowers and 42 plants with white flowers.

Question 77

In a certain breed of chicken, two genes control color.A dominant allele (I) inhibits the expression of any color gene (C).A second recessive gene (c) results in albinism when homozygous (cc).Give the F₂ phenotypic ratio of a colored chicken ii CC with a white II cc.

Question 78

Pure-breeding yellow guinea pigs crossed with pure-breeding white ones produce only cream-colored offspring.This pattern indicates incomplete dominance.Rough hair is found to be dominant to smooth hair.Give the F₁ and F₂ genotypic and phenotypic ratios of a cross of a smooth, white guinea pig with a homozygous, rough, yellow guinea pig.

Question 79

MATCHING
Classification.Answer the following questions using the group of answers below.
a.4
b.6
c.8
d.12
e.24
In a dihybrid cross between a parent that is a double heterozygote (Aa Bb) and a parent that is homozygous dominant for one gene and heterozygous for the other (AA Bb), how many unique genotypes potentially will be present in their offspring?

Question 80

Congenital deafness in humans is due to the homozygous condition of either of the recessive genes d or e, or both of these genes.Both dominant D and E are necessary for normal hearing.Gene D/d affects the middle ear, while gene E/e affects the inner ear.It does not matter how good the normal inner ear (as indicated by E__) is; if there is something wrong in the middle ear, the individual is unable to hear.The same applies for the other gene.Give the phenotypic results of the following crosses:
(a)
Dd EE * Dd EE
(b)
Dd Ee *Dd Ee
(c)
dd EE * DD ee
(d)
Dd EE *Dd ee
(e)
Dd EE * DD Ee