Question 1

In a cross between a homozygous curly-haired person and a homozygous straight-haired person, curly hair is dominant over straight hair. What percentage of their offspring would be expected to have straight hair?

Accepted Answer

0%

Question 2

In snapdragons, red flowers (RR) and white flowers (rr) show incomplete dominance, resulting in pink flowers (Rr). If a pink-flowered plant is crossed with a white-flowered plant, what is the expected ratio of flower colors in the offspring?

Accepted Answer

1 pink : 1 white

Question 3

A mother has type A blood and her son has type O blood. What are the possible blood types of the son's father?

Accepted Answer

Types A, B, or O

Question 4

Suppose coat color in rabbits is controlled by two genes (E and C), each showing complete dominance. The relationship between genotype and phenotype is as follows: EE or Ee = brown, ee = albino; CC or Cc = black, cc = white. If two brown rabbits produce an albino baby rabbit, what are the genotypes of each parent and the baby?

Accepted Answer

Both parents: Ee; baby: ee

Question 5

You breed guinea pigs and notice that two genes are responsible for the trait of coat color. When you cross two guinea pigs with the same genotype, you observe a 9:3:3:1 ratio in the offspring. What does this ratio indicate?

Accepted Answer

It is a dihybrid cross

Question 6

Multiple mutations found in a single gene are said to belong to the same ______ group.

Accepted Answer

Complementation

Question 7

Duchenne muscular dystrophy is caused by a recessive X-linked allele. A man with this disorder ______.

Accepted Answer

Must have inherited it from his mother

Question 8

A female carrier for color blindness (an X-linked recessive trait) marries a man with normal vision. What proportion of their sons will be color blind?

Accepted Answer

$$\frac{1}{2}$$

Question 9

In a pedigree, genetic control of blindness is shown. Blind individuals are shaded black. If drugs A and B are used to treat blindness, and only individuals with genotype aa are blind, which inheritance pattern is consistent with the pedigree?

Accepted Answer

Autosomal recessive

Question 10

A scientist is studying heart development in zebrafish and uses a complementation test to determine whether two mutations are in the same gene. If cross 1 (mutant A x mutant B) results in wild-type offspring, and cross 2 (mutant A x mutant A) results in mutant offspring, what can be concluded?

Accepted Answer

Mutations are in different genes

Question 11

If a trait is controlled by two genes showing epistasis, and the F2 generation shows a 9:7 ratio, what does this suggest about the genetic interaction?

Accepted Answer

Both genes are required for the trait

Question 12

A man with blood type AB marries a woman with blood type O. What are the possible blood types of their children?

Accepted Answer

A and B

Question 13

In a population, the frequency of allele A is $$p = 0.7$$ and allele a is $$q = 0.3. $$According to Hardy-Weinberg equilibrium, what is the expected frequency of heterozygotes?

Accepted Answer

$$2pq = 0.42$$

Question 14

A woman who is a carrier for hemophilia (an X-linked recessive disorder) has children with a man who does not have hemophilia. What is the probability that their daughter will have hemophilia?

Accepted Answer

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

Question 15

Which of the following best describes the concept of complementation in genetics?

Accepted Answer

Two mutations in different genes restore the wild-type phenotype when combined

Question 16

A pedigree shows a trait that skips generations and affects both males and females equally. What is the most likely mode of inheritance?

Accepted Answer

Autosomal recessive

Question 17

If a male with genotype $$X^cY ($$where $$X^c is $$the color-blind allele) and a female with genotype $$X^CX^c$$ have children, what is the probability that a daughter will be color blind?

Accepted Answer

$$\frac{1}{2}$$

Question 18

Which of the following is NOT a feature of X-linked recessive inheritance?

Accepted Answer

Affected males can pass the allele to their sons

Question 19

A test cross is performed between a heterozygous tall pea plant ($$Tt) $$and a homozygous recessive dwarf plant ($$tt). $$What is the expected phenotypic ratio in the offspring?

Accepted Answer

1 tall : 1 dwarf

Genetics Exam Questions and Explanations: Mendelian Inheritance, Blood Types, and Genetic Disorders

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