Question 1

An incompletely dominant gene controls the color of chickens so that BB produces black, Bb produces a slate-gray color called blue, and bb produces splashed white.A second gene controls comb shape, with the dominant gene R producing a rose comb and r producing a single comb.If a pure-breeding, black chicken with a rose comb is mated to a splashed-white chicken with a single comb in the F₂ generation, what fraction of the offspring will be blue with rose comb? A)9/16 B)3/8 C)3/16 D)1/8 E)1/16

Accepted Answer

The answer of An incompletely dominant gene controls the color...

Question 2

If red (RR) is crossed with white (rr) and produces a pink flower (Rr), and tall (D) is dominant to dwarf (d), the F₂ phenotypic ratio from a cross of RR dd with rr DD would be A)9:3:3:1. B)1:1:1:1. C)1:2:2:4:1:2:1:2:1. D)3:6:3:1:2:1. E)none of these.

Accepted Answer

The phenotype of the parent with red flowers and dwarf stature is RR dd, while the other parent with white flowers and tall stature is rr DD. Therefore, when they are crossed, their offspring will be Rr Dd, Rr DD, rr dd, and rr Dd.

The phenotype of Rr Dd is pink flowers and tall stature. The phenotype of Rr DD is pink flowers and tall stature. The phenotype of rr dd is white flowers and dwarf stature. The phenotype of rr Dd is white flowers and dwarf stature.

Therefore, the phenotypic ratio of the offspring is 3 pink and tall: 6 white and dwarf: 3 pink and dwarf: 1 white and tall: 2 pink and heterozygous for dwarf: 1 white and heterozygous for tall. This can be simplified to 3:6:3:1:2:1, which is the ratio in choice D.

Question 3

An incompletely dominant gene controls the color of chickens so that BB produces black, Bb produces a slate-gray color called blue, and bb produces splashed white.A second gene controls comb shape, with the dominant gene R producing a rose comb and r producing a single comb.If a pure-breeding, black chicken with a rose comb is mated to a splashed-white chicken with a single comb in the F₂ generation, what fraction of the offspring will be blue with single comb? A)9/16 B)3/8 C)3/16 D)1/8 E)1/16

Accepted Answer

The answer of An incompletely dominant gene controls the color...

Question 4

Multiple effects of a single gene is
A)expressivity.
B)penetrance.
C)codominance.
D)pleiotropy.
E)multiple alleles.

Accepted Answer

Pleiotropy refers to the phenomenon where a single gene can affect multiple traits or have multiple effects on the phenotype. This is different from expressivity, which refers to the degree to which a gene is expressed, and from penetrance, which refers to the proportion of individuals carrying a particular gene who actually express the associated phenotype. Codominance and multiple alleles refer to specific types of genetic inheritance and do not necessarily involve the idea of a gene affecting multiple traits.

Question 5

In radishes, red and white are the pure-breeding colors, and long and round are the pure-breeding shapes, while the hybrids are purple and oval.The cross of a red oval with a purple oval will produce all BUT which of the following phenotypes?
A)white and long
B)purple and oval
C)red and oval
D)purple and long
E)red and long

Accepted Answer

The cross between a red oval and a purple oval will produce all purple and oval offspring. Therefore, white and long (due to the absence of red and round alleles) will not be present in the offspring.

Question 6

In radishes, red and white are the pure-breeding colors, and long and round are the pure-breeding shapes, while the hybrids are purple and oval.The cross of a purple oval with a purple oval
A)is a cross between two pure-breeding forms.
B)is an example of a testcross.
C)produces only homozygous pure-breeding forms.
D)produces only heterozygous offspring.
E)none of these are true.

Accepted Answer

The cross of a purple oval with a purple oval involves hybrids, not pure-breeding forms, and can produce a mix of homozygous and heterozygous offspring, not exclusively one type.

Question 7

In radishes, red and white are the pure-breeding colors, and long and round are the pure-breeding shapes, while the hybrids are purple and oval.The cross of a white oval and a purple oval will produce more
A)red long than white long.
B)purple round than white long.
C)purple oval than purple long.
D)purple long than purple round.
E)purple round than white oval.

Accepted Answer

The hybrid purple oval radishes are heterozygous for both color and shape. Crossing two purple ovals will produce more purple ovals than purple longs due to the higher probability of inheriting the oval shape.

Question 8

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.

Accepted Answer

A pleiotropic gene is a gene that produces multiple effects, such as affecting multiple traits or having multiple functions in the body. This is in contrast to a multiple allele, which refers to a gene that exists in different versions, or an epistatic gene, which refers to a gene that affects the expression of another gene. Autosomes refer to the chromosomes that are not sex chromosomes, while incomplete dominance refers to a situation where neither allele is completely dominant over the other, resulting in an intermediate phenotype.

Question 9

If one pair of alleles exhibits simple dominance while the other pair exhibits incomplete dominance, the F₂ phenotype produced from a cross of AA BB with aa bb will produce a __________ ratio. A)1:1:1:1 B)9:3:3:1 C)1:4:6:4:1 D)1:2:1 E)3:6:3:1:2:1

Accepted Answer

The F2 generation from a cross of AA BB with aa bb, where one allele pair shows simple dominance and the other shows incomplete dominance, will produce a 3:6:3:1:2:1 phenotypic ratio.

Question 10

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.

Accepted Answer

The answer of The F₂ phenotypic ratio of 9:3:4 is...

Question 11

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.

Accepted Answer

Genes at one locus that affect the expression of genes at a different locus are known as epistatic. This means that the presence of one gene can alter the expression of genes at another locus, potentially masking or modifying their effects. Linked genes refers to genes that are physically located close together on a chromosome and tend to be inherited together. Codominant refers to a situation where both alleles of a gene are expressed equally. Penetrance refers to the proportion of individuals with a particular genotype who exhibit the corresponding phenotype. Alleles are different versions of a gene that code for different traits.

Question 12

Roan cattle are the heterozygous hybrids of a cross between a white individual and a red individual.If a roan bull were crossed with a red cow, their offspring would show which of the following ratios?
A)all roan
B)1 red: 2 roan: 1 white
C)1 red: 1 white
D)1 red: 1 roan
E)all red

Accepted Answer

When a roan bull (Rr) is crossed with a red cow (rr), the offspring can have two possible genotypes: Rr or rr. Therefore, the offspring will either be roan (Rr) or red (rr), with a 1:1 ratio of red to roan. There will be no white offspring since white is a recessive trait that is masked in heterozygous individuals (Rr). Therefore, the correct ratio is 1 red: 1 roan.

Question 13

An incompletely dominant gene controls the color of chickens so that BB produces black, Bb produces a slate-gray color called blue, and bb produces splashed white.A second gene controls comb shape, with the dominant gene R producing a rose comb and r producing a single comb.If a pure-breeding, black chicken with a rose comb is mated to a splashed-white chicken with a single comb in the F₂ generation, what fraction of the offspring will be black with rose comb? A)9/16 B)3/8 C)3/16 D)1/8 E)1/16

Accepted Answer

The F2 generation results from crossing BbRr x BbRr. The probability of black (BB) is 1/4, and the probability of rose comb (R-) is 3/4. Multiplying these probabilities gives 1/4 * 3/4 = 3/16.

Question 14

In radishes, red and white are the pure-breeding colors, and long and round are the pure-breeding shapes, while the hybrids are purple and oval.The cross of a red, long radish and a white, round radish will produce an F₂ generation in which A)the most common phenotype will be oval and purple. B)the purple color will occur with all three shapes of radish. C)the red color will occur with all three shapes of radish. D)all white, long forms produced will be pure-breeding. E)all of these are true.

Accepted Answer

The F₂ generation is a result of a dihybrid cross between the two pure-breeding parents. The letters represent the genes and their corresponding alleles for color and shape. F and U represent the alleles for red and white color, respectively, while B and S represent the alleles for long and round shape, respectively. The most common phenotype will be oval and purple (choice A) because these are the traits of the hybrid offspring produced from the cross of the two pure-breeding parents. The purple color will occur with all three shapes of radish (choice B) because the purple trait is dominant over both red and white, and will therefore be expressed in any offspring that inherits at least one copy of the purple allele. The red color will occur with all three shapes of radish (choice C) because the red allele is still present in the F₂ generation, even if it is not expressed in the phenotype. Not all white, long forms produced will be pure-breeding (choice D) because the white and long traits are both recessive, and an offspring must inherit two copies of each allele to be pure-breeding for those traits. It is possible that a white, long offspring could be heterozygous for one or both traits, and therefore not pure-breeding.

Question 15

In radishes, red and white are the pure-breeding colors, and long and round are the pure-breeding shapes, while the hybrids are purple and oval.The cross of a red, long radish and a white, round radish will produce an F₁ generation of what phenotype? A)all long, red radishes B)all long, white radishes C)all long, purple radishes D)all round, purple radishes E)none of these

Accepted Answer

The answer of In radishes, red and white are the...

Question 16

A cross between a rose comb chicken (RRpp) and a pea comb chicken (rrPP) produces all walnut comb chickens (RrPp).This outcome is a result of
A)environmental factors.
B)two interacting gene pairs affecting one trait.
C)a gene mutation in the rose comb chicken.
D)pleiotropic effects of the P gene product.
E)continuous variation in phenotypes.

Accepted Answer

The outcome of the cross suggests that two gene pairs, one for comb shape and one for pigmentation, are interacting to produce the walnut comb phenotype. The inheritance pattern of this trait is consistent with Mendelian genetics, specifically the principle of independent assortment. Environmental factors would not produce such clear and predictable results, and a gene mutation in the rose comb chicken would not account for the offspring's phenotype. Pleiotropy and continuous variation may be involved in other traits, but they are not relevant to this particular scenario.

Question 17

If all the offspring of a cross have the genotype Aa Bb, the parents of the cross will most likely be
A)AA BB x aa bb.
B)AA bb x aa BB.
C)Aa Bb x Aa Bb.
D)Aa bb x aa Bb.
E)AA BB x aa bb or AA bb x aa BB.

Accepted Answer

The answer of If all the offspring of a cross...

Question 18

If shape and color of radishes are due to incompletely dominant genes, crossing two dihybrid heterozygotes will produce how many different phenotypes?
A)2
B)3
C)4
D)5
E)9

Accepted Answer

Incomplete dominance means that neither allele is dominant over the other, and the heterozygote has a phenotype that is intermediate between the two homozygotes. In this case, the heterozygote will have a phenotype that is a blend of the two homozygotes. For example, if one homozygote has red radishes and the other homozygote has white radishes, the heterozygote will have pink radishes.When two dihybrid heterozygotes are crossed, the offspring will have a variety of phenotypes. The possible phenotypes are:- Red radishes- White radishes- Pink radishes- Purple radishes- Orange radishesThe number of different phenotypes is 5.

Question 19

In a cross involving plants with round/wrinkled seeds, yellow/green pods, and tall/dwarf stems, the researcher is actually observing __________traits.
A)4
B)3
C)6
D)12
E)none of these

Accepted Answer

The researcher is observing three traits: seed shape (round/wrinkled), pod color (yellow/green), and stem height (tall/dwarf). Each trait has two possible variations (round or wrinkled, yellow or green, tall or dwarf), resulting in a total of 2x2x2=8 possible phenotypes. However, since each individual plant can only have one variation for each trait, the actual observed phenotypes will only be a subset of the possible 8. Therefore, the researcher is observing three traits with two possible variations each, for a total of six observed phenotypes.

Question 20

Coat color in one breed of mice is controlled by incompletely dominant alleles so that yellow and white are homozygous while cream is heterozygous.The cross of two cream individuals will produce
A)all cream offspring.
B)equal numbers of white and yellow mice, but no cream offspring.
C)equal numbers of white and cream mice.
D)equal numbers of yellow and cream mice.
E)equal numbers of white and yellow mice, with twice as many creams as the other two colors.

Accepted Answer

When two cream mice (heterozygous) are crossed, the offspring will be in a 1:2:1 ratio of yellow (homozygous), cream (heterozygous), and white (homozygous), respectively. This results in equal numbers of white and yellow mice, with twice as many creams.

Quiz 11: Observing Patterns in Inherited Traits

If red (RR) is crossed with white (rr) and produces a pink flower (Rr) , and tall (D) is dominant to dwarf (d) , the F₂ phenotypic ratio from a cross of RR dd with rr DD would be

Multiple effects of a single gene is

In radishes, red and white are the pure-breeding colors, and long and round are the pure-breeding shapes, while the hybrids are purple and oval.The cross of a red oval with a purple oval will produce all BUT which of the following phenotypes?

In radishes, red and white are the pure-breeding colors, and long and round are the pure-breeding shapes, while the hybrids are purple and oval.The cross of a purple oval with a purple oval

In radishes, red and white are the pure-breeding colors, and long and round are the pure-breeding shapes, while the hybrids are purple and oval.The cross of a white oval and a purple oval will produce more

A gene that produces multiple effects is called

If one pair of alleles exhibits simple dominance while the other pair exhibits incomplete dominance, the F₂ phenotype produced from a cross of AA BB with aa bb will produce a __________ ratio.

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

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

Roan cattle are the heterozygous hybrids of a cross between a white individual and a red individual.If a roan bull were crossed with a red cow, their offspring would show which of the following ratios?

In radishes, red and white are the pure-breeding colors, and long and round are the pure-breeding shapes, while the hybrids are purple and oval.The cross of a red, long radish and a white, round radish will produce an F₂ generation in which

In radishes, red and white are the pure-breeding colors, and long and round are the pure-breeding shapes, while the hybrids are purple and oval.The cross of a red, long radish and a white, round radish will produce an F₁ generation of what phenotype?

A cross between a rose comb chicken (RRpp) and a pea comb chicken (rrPP) produces all walnut comb chickens (RrPp) .This outcome is a result of

If all the offspring of a cross have the genotype Aa Bb, the parents of the cross will most likely be

If shape and color of radishes are due to incompletely dominant genes, crossing two dihybrid heterozygotes will produce how many different phenotypes?

In a cross involving plants with round/wrinkled seeds, yellow/green pods, and tall/dwarf stems, the researcher is actually observing __________traits.

Coat color in one breed of mice is controlled by incompletely dominant alleles so that yellow and white are homozygous while cream is heterozygous.The cross of two cream individuals will produce