Question 1

Genes that are _____ do not assort independently and are said to be _____.

Accepted Answer

Genes that are close to each other on the same chromosome do not assort independently and are said to be linked. This is because they are physically attached to the same chromosome and cannot separate during meiosis as easily as genes on different chromosomes can.

Question 2

Mendel's principle of independent assortment corresponds to which part of meiosis?

Accepted Answer

Mendel's principle of independent assortment states that alleles of different genes segregate independently of each other during meiosis. This means that the assortment of chromosomes during meiosis I is random, and homologous chromosomes can align on the metaphase plate in any combination. Therefore, the principle of independent assortment corresponds to the random alignment of homologs on the metaphase plate during metaphase I.

Question 3

You cross a true-breeding stock of black (BB) mice with skinny (SS) toes to a stock of white (bb) mice with fat (ss) toes. From this, you produce an F₁ generation of black mice with skinny toes (Bb,Ss). If the single genes responsible for coat color and toe appearance do not sort independently, then you would expect to see:

Accepted Answer

If the genes do not sort independently, they are likely linked, meaning they are located close to each other on the same chromosome. This linkage would result in a higher frequency of parental phenotypes (black with skinny toes) in the F2 generation, leading to more than 75% of black mice having skinny toes.

Question 4

With independent assortment, the ratio of phenotypes in the F₂ generation of a cross between true-breeding strains (AA bb × aa BB) can be described as 9:3:3:1 when A and B are dominant over a and b. What phenotype does the "9" in the ratio refer to?

Accepted Answer

The "9" in the ratio refers to the phenotype that is dominant for both traits, represented by the genotype AaBb. This is because it is the only genotype that can result in both dominant traits being expressed, and it is present in 9 out of the 16 possible offspring in the F₂ generation.

Question 5

The principle of independent assortment states that:

Accepted Answer

The principle of independent assortment states that alleles of a gene pair assort independently of other gene pairs. This means that the inheritance of one trait does not affect the inheritance of another trait, as they assort into gametes independently.

Question 6

Genes that fail to show independent assortment are said to be linked.

Accepted Answer

Linked genes are those that are located close to each other on the same chromosome and tend to be inherited together, as they do not show independent assortment during meiosis.

Question 7

Genes on different chromosomes _____ during meiosis. Genes that are very close together on the same chromosome are _____.

Accepted Answer

Genes on different chromosomes assort independently during meiosis according to Mendel's law of independent assortment. Genes that are very close together on the same chromosome tend to be inherited together and are described as linked.

Question 8

In genetics, the dash symbol (-) is a "wild card" that stands for either the dominant allele or the recessive allele; for example, A- means the individual has either the genotype AA or Aa. Two genes that undergo independent assortment affect fruit color in summer squash. Each gene has two alleles, one of which is dominant for fruit color. Genotypes of the form A- B- and A- bb have white fruit, genotypes of the form aa B- have yellow fruit, and genotype aa bb has green fruit. What ratio of white : yellow : green is expected from the cross Aa Bb × Aa Bb?

Accepted Answer

The answer of In genetics, the dash symbol (-) is...

Question 9

In humans, ability to roll the tongue (R) is dominant to being unable to roll (r). Having freckles (F) is dominant to having no freckles (f). A man heterozygous for both traits marries a woman heterozygous for both traits. What is the probability that they will have a child with freckles?

Accepted Answer

The answer of In humans, ability to roll the tongue...

Question 10

You are given two populations of true-breeding tomato plants with two traits that sort independently. Using the multiplication rule, how many of the F₂ progeny would you expect to have a recessive phenotype for both traits?

Accepted Answer

The multiplication rule states that the probability of two independent events both occurring is the product of their individual probabilities. For two traits that sort independently, if each trait has a recessive phenotype probability of 1/4 (since the plants are true-breeding, implying a simple Mendelian inheritance with a dominant and recessive allele for each trait), then the probability of an offspring having both recessive phenotypes is 1/4 * 1/4 = 1/16.

Question 11

In pea plants, flowers are either white or purple; the purple color is produced by pigments called anthocyanins. The production of anthocyanins is a two-step process: the first is controlled by the C gene and the second by the P gene. Both genes must produce functional proteins for anthocyanin to be expressed. For each gene, the dominant (C and P) alleles produce functional proteins. You cross two pea plants, each with the genotype CcPp. What proportion of their offspring will have white flowers?

Accepted Answer

The offspring will have white flowers if they have either cc or pp genotype. The probability of cc is 1/4, and the probability of pp is 1/4. The probability of either cc or pp (or both) is 1/4 + 1/4 - 1/16 = 7/16.

Question 12

When one gene is able to modify the effect of a second gene, the phenomenon is known as:

Accepted Answer

Epistasis occurs when the expression of one gene depends on the presence of one or more modifier genes. In this case, the modifier gene can change or influence the effect of another gene, leading to different phenotypic outcomes. This is different from simple dominance, which involves the expression of one dominant gene over a recessive gene. Independent assortment and segregation relate to the segregation and distribution of alleles during meiosis.

Question 13

Mendel was the first to demonstrate:

Accepted Answer

Mendel's experiments with pea plants provided evidence for all of these genetic principles. He observed dominance of certain traits over others, segregation of alleles during gamete formation, independent assortment of genes on different chromosomes, and the equivalence of reciprocal crosses (meaning that the same results were obtained regardless of which parent was used as the male or female in the cross).

Question 14

The breeding example of White Leghorn chickens and White Wyandotte chickens, in which more than one gene controls pigment production, is an example of _____ interactions between genes.

Accepted Answer

Epistasis is a type of gene interaction in which the expression of one gene affects the expression of another gene. In the example of White Leghorn chickens and White Wyandotte chickens, the gene that controls pigment production in Leghorn chickens is epistatic to the gene that controls pigment production in Wyandotte chickens. This means that the expression of the Wyandotte gene for pigment production is dependent on the presence or absence of the Leghorn gene. Therefore, this is an example of epistatic interactions between genes.

Question 15

Genes that modify the expression of other genes show:

Accepted Answer

Epistasis refers to when one gene modifies the expression of another gene. This can result in a range of outcomes, including masking or enhancing the expression of the other gene. None of the other answer choices specifically address this phenomenon.

Question 16

In genetics, the dash symbol (-) is a "wild card" that stands for either the dominant allele or the recessive allele; for example, A- means the individual has either the genotype AA or Aa. Two genes that undergo independent assortment affect coat color in Duroc pigs. Each gene has two alleles, one of which is dominant for coat color. Genotypes of the form A- B- are red, those of the form A- bb and aa B- are sandy, and genotype aa bb is white. What ratio of red : sandy : white is expected from the cross Aa Bb × Aa Bb?

Accepted Answer

The answer of In genetics, the dash symbol (-) is...

Question 17

Recall that in Mendel's work, mating between yellow, wrinkled, seed-producing plants and plants that produced smooth green seeds resulted in a ratio of 9:3:3:1 for progeny phenotypes (refer to Fig. 16.12). This observed ratio can be explained by:

Accepted Answer

The 9:3:3:1 ratio observed in Mendel's dihybrid crosses is explained by the principle of independent assortment, which states that alleles of different genes assort independently of one another during gamete formation. The multiplication rule is used to predict the probability of two independent events both occurring, which is applicable here for calculating the combined probabilities of inheriting two independent traits.

Question 18

You are given two true-breeding groups of gerbils. The gerbils in the first group have black coat color and curly tails; the gerbils in the second group have yellow coat color and straight tails. When you produce an F₁ generation, you see only gerbils with black coat color and curly tails. When you produce an F₂ generation, you see some gerbils with black coat color (75%) and some gerbils with yellow coat color (25%). You also see that some of the gerbils have straight tails (25%) and others (75%) have curly tails. If the single alleles responsible for coat color and tail appearance sort independently, how many of the black gerbils in this generation are expected to have straight tails?

Accepted Answer

Since the single alleles responsible for coat color and tail appearance sort independently, the 75% of black gerbils are expected to have curly tails and the remaining 25% of black gerbils are expected to have straight tails. Therefore, the answer is 25%.

Question 19

Which of the following statements are hallmarks of Mendel's Laws?

Accepted Answer

The statement "The alleles of a given gene will segregate as gametes are formed" is one of the hallmarks of Mendel's Laws, specifically the Law of Segregation. The other statements in the options do not accurately reflect Mendel's Laws.

Question 20

For unlinked genes, the sorting of one gene pair influences the sorting of another gene pair.

Accepted Answer

Unlinked genes assort independently during meiosis and their sorting does not influence the sorting of another gene pair.

Quiz 16: Mendelian Inheritance

Genes that are _ do not assort independently and are said to be _.

Mendel's principle of independent assortment corresponds to which part of meiosis?

With independent assortment, the ratio of phenotypes in the F₂ generation of a cross between true-breeding strains (AA bb × aa BB) can be described as 9:3:3:1 when A and B are dominant over a and b. What phenotype does the "9" in the ratio refer to?

The principle of independent assortment states that:

Genes that fail to show independent assortment are said to be linked.

Genes on different chromosomes _ during meiosis. Genes that are very close together on the same chromosome are _.

In humans, ability to roll the tongue (R) is dominant to being unable to roll (r) . Having freckles (F) is dominant to having no freckles (f) . A man heterozygous for both traits marries a woman heterozygous for both traits. What is the probability that they will have a child with freckles?

You are given two populations of true-breeding tomato plants with two traits that sort independently. Using the multiplication rule, how many of the F₂ progeny would you expect to have a recessive phenotype for both traits?

When one gene is able to modify the effect of a second gene, the phenomenon is known as:

Mendel was the first to demonstrate:

The breeding example of White Leghorn chickens and White Wyandotte chickens, in which more than one gene controls pigment production, is an example of _____ interactions between genes.

Genes that modify the expression of other genes show:

Recall that in Mendel's work, mating between yellow, wrinkled, seed-producing plants and plants that produced smooth green seeds resulted in a ratio of 9:3:3:1 for progeny phenotypes (refer to Fig. 16.12) . This observed ratio can be explained by:

Which of the following statements are hallmarks of Mendel's Laws?

For unlinked genes, the sorting of one gene pair influences the sorting of another gene pair.

Quiz 16: Mendelian Inheritance

Genes that are _____ do not assort independently and are said to be _____.

Mendel's principle of independent assortment corresponds to which part of meiosis?

With independent assortment, the ratio of phenotypes in the F2 generation of a cross between true-breeding strains (AA bb × aa BB) can be described as 9:3:3:1 when A and B are dominant over a and b. What phenotype does the "9" in the ratio refer to?

The principle of independent assortment states that:

Genes that fail to show independent assortment are said to be linked.

Genes on different chromosomes _____ during meiosis. Genes that are very close together on the same chromosome are _____.

In humans, ability to roll the tongue (R) is dominant to being unable to roll (r) . Having freckles (F) is dominant to having no freckles (f) . A man heterozygous for both traits marries a woman heterozygous for both traits. What is the probability that they will have a child with freckles?

You are given two populations of true-breeding tomato plants with two traits that sort independently. Using the multiplication rule, how many of the F2 progeny would you expect to have a recessive phenotype for both traits?

When one gene is able to modify the effect of a second gene, the phenomenon is known as:

Mendel was the first to demonstrate:

The breeding example of White Leghorn chickens and White Wyandotte chickens, in which more than one gene controls pigment production, is an example of _____ interactions between genes.

Genes that modify the expression of other genes show:

Recall that in Mendel's work, mating between yellow, wrinkled, seed-producing plants and plants that produced smooth green seeds resulted in a ratio of 9:3:3:1 for progeny phenotypes (refer to Fig. 16.12) . This observed ratio can be explained by:

Which of the following statements are hallmarks of Mendel's Laws?

For unlinked genes, the sorting of one gene pair influences the sorting of another gene pair.

Genes that are _ do not assort independently and are said to be _.

With independent assortment, the ratio of phenotypes in the F₂ generation of a cross between true-breeding strains (AA bb × aa BB) can be described as 9:3:3:1 when A and B are dominant over a and b. What phenotype does the "9" in the ratio refer to?

Genes on different chromosomes _ during meiosis. Genes that are very close together on the same chromosome are _.

You are given two populations of true-breeding tomato plants with two traits that sort independently. Using the multiplication rule, how many of the F₂ progeny would you expect to have a recessive phenotype for both traits?