Question 1

Which of the following statements best describes the inheritance pattern of autosomal dominant traits, as illustrated in the pedigree diagram?

Accepted Answer

Autosomal dominant traits appear in every generation and affect males and females equally.

Question 2

Pseudoachondroplasia is an example of which type of genetic inheritance?

Accepted Answer

Autosomal dominant

Question 3

In a family where one parent is heterozygous for an autosomal dominant trait and the other is unaffected, what is the expected proportion of affected offspring?

Accepted Answer

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

Question 4

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

Accepted Answer

Unaffected individuals can transmit the trait to their offspring.

Question 5

Sweet peas (Lathyrus odoratus) exhibit a 9:7 ratio among progeny in certain genetic crosses. What does this ratio indicate?

Accepted Answer

Gene interaction involving two loci

Question 6

Which process is responsible for the genetic variation seen in offspring produced by sexual reproduction?

Accepted Answer

Meiosis

Question 7

In the alternation of haploid and diploid states during sexual reproduction, which event restores the diploid number?

Accepted Answer

Fertilization

Question 8

Which of the following statements about sex determination in humans is correct?

Accepted Answer

The presence of the SRY gene on the Y chromosome determines maleness.

Question 9

In birds, which sex is heterogametic and what is their sex chromosome composition?

Accepted Answer

Female; ZW

Question 10

Which of the following is a model genetic organism used to study inheritance patterns, as shown in the provided images?

Accepted Answer

Drosophila melanogaster (fruit fly)

Question 11

Which genetic cross would you use to determine if a trait is X-linked recessive in Drosophila?

Accepted Answer

Perform reciprocal crosses between red-eyed and white-eyed flies and compare F1 results.

Question 12

Which of the following best explains why X-linked recessive traits, such as red-green color blindness, are more common in males than females?

Accepted Answer

Males are hemizygous for X-linked genes, so a single recessive allele causes the phenotype.

Question 13

A woman with hemophilia (an X-linked recessive disorder) mates with a man who has normal blood clotting. What is the probability that their child will have hemophilia?

Accepted Answer

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

Question 14

Which of the following statements about Barr bodies is correct?

Accepted Answer

Barr bodies are inactivated X chromosomes found in female cells.

Question 15

A male with the genotype XXXYY will have how many Barr bodies in each of his cells?

Accepted Answer

$$3$$

Question 16

Which of the following best describes incomplete dominance?

Accepted Answer

The heterozygote has a phenotype intermediate between those of the two homozygotes.

Question 17

In the ABO blood group system, which genotype results in the AB blood type?

Accepted Answer

$$I^A I^B$$

Question 18

Which of the following is an example of codominance?

Accepted Answer

AB blood type expressing both A and B antigens

Extensions and Modifications of Basic Principles in Genetics

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