Q: In a dihybrid cross between two heterozygous pea plants (RrGg x RrGg), what is the probability that an offspring will be round and yellow? Use the product rule to solve.

$$ \frac{3}{4} \times \frac{3}{4} = \frac{9}{16} $$

Q: In a dihybrid cross, what is the probability of obtaining an offspring with wrinkled and green seeds (rrgg) from RrGg x RrGg?

$$ \frac{1}{4} \times \frac{1}{4} = \frac{1}{16} $$

Q: In a trihybrid cross (RrGgPp x RrGgPp), what is the probability of obtaining an offspring that is homozygous recessive for all three genes?

$$ \frac{1}{4} \times \frac{1}{4} \times \frac{1}{4} = \frac{1}{64} $$

Q: If a parent is heterozygous for three genes (RrGgPp), what is the probability that a gamete will contain the alleles rgp?

$$ \frac{1}{2} \times \frac{1}{2} \times \frac{1}{2} = \frac{1}{8} $$

Question 1

In a dihybrid cross between two heterozygous pea plants (RrGg x RrGg), what is the probability that an offspring will be round and yellow? Use the product rule to solve.

Accepted Answer

$$ \frac{3}{4} 	imes \frac{3}{4} = \frac{9}{16} $$

Question 2

Which of the following best describes Mendel’s law of independent assortment?

Accepted Answer

Alleles for different genes segregate independently during gamete formation.

Question 3

A trihybrid cross is performed: RrGgPp x RrGgPp. How many distinct phenotypes are possible in the F2 generation?

Accepted Answer

$$ 2^3$ = 8 $$

Question 4

In a dihybrid cross, what is the probability of obtaining an offspring with wrinkled and green seeds (rrgg) from RrGg x RrGg?

Accepted Answer

$$ \frac{1}{4} 	imes \frac{1}{4} = \frac{1}{16} $$

Question 5

If a pea plant with genotype RrGg is crossed with a plant with genotype rrgg, what is the expected phenotypic ratio among the offspring?

Accepted Answer

1:1:1:1

Question 6

What is the probability that a yellow-seeded offspring from a Gg x Gg cross is heterozygous? (Conditional probability)

Accepted Answer

$$ \frac{2}{3} $$

Question 7

In a pedigree, which feature is characteristic of autosomal dominant inheritance?

Accepted Answer

Each affected individual has at least one affected parent.

Question 8

How many distinct genotypes are possible in a cross of AaBbCcDd x AaBbCcDd?

Accepted Answer

$$ 3^4$ = 81 $$

Question 9

Which rule of probability is used to calculate the likelihood of either of two mutually exclusive events occurring?

Accepted Answer

Sum rule (addition rule)

Question 10

A pedigree shows two parents who do not express a recessive trait, but their child does. What are the most likely genotypes of the parents?

Accepted Answer

Both are heterozygous (Dd)

Question 11

In a trihybrid cross (RrGgPp x RrGgPp), what is the probability of obtaining an offspring that is homozygous recessive for all three genes?

Accepted Answer

$$ \frac{1}{4} 	imes \frac{1}{4} 	imes \frac{1}{4} = \frac{1}{64} $$

Question 12

Which of the following best explains why Mendel observed a 9:3:3:1 ratio in the F2 generation of a dihybrid cross?

Accepted Answer

The alleles for each gene assort independently during gamete formation.

Question 13

In a dihybrid test cross (RrGg x rrgg), what is the expected phenotypic ratio among the offspring?

Accepted Answer

1:1:1:1

Question 14

If a pedigree shows a trait appearing in every generation and affecting both males and females equally, which inheritance pattern is most likely?

Accepted Answer

Autosomal dominant

Question 15

A woman and a man each have a sibling with an autosomal recessive condition, but neither expresses the trait. What is the probability that their first child will have the condition?

Accepted Answer

$$ \frac{1}{4} $$

Question 16

Which event during meiosis is responsible for the independent assortment of alleles?

Accepted Answer

Random alignment of homologous chromosomes during metaphase I

Question 17

In a cross AaBbCc x aabbcc, how many distinct genotypes are possible among the offspring?

Accepted Answer

$$ 2^3$ = 8 $$

Question 18

Which of the following is NOT a characteristic of autosomal recessive inheritance?

Accepted Answer

Trait is seen in every generation

Question 19

If a parent is heterozygous for three genes (RrGgPp), what is the probability that a gamete will contain the alleles rgp?

Accepted Answer

$$ \frac{1}{2} 	imes \frac{1}{2} 	imes \frac{1}{2} = \frac{1}{8} $$

Question 20

In a dihybrid cross, what is the probability of obtaining an offspring that is heterozygous for both genes (RrGg)?

Accepted Answer

$$ \frac{1}{4} $$

Transmission Genetics: Mendelian Inheritance, Probability, and Pedigree Analysis CH 2 NEW SEM

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