3. Extensions to Mendelian Inheritance

Which of the follow sex chromosomes can be describes as homogametic?

In the ZZ/ZW sex determination system, the male is…?

In humans, which region on the Y chromosome determines maleness?

During meiosis the XY sex chromosomes segregate independently. Which of the following represents the gametes chromosomes after meiosis?

How do we know that X chromosomal inactivation of either the paternal or maternal homolog is a random event during early development in mammalian females?

How do we know that Drosophila utilizes a different sex-determination mechanism than mammals, even though it has the same sex-chromosome compositions in males and females?

How do we know that in humans the X chromosomes play no role in human sex determination, while the Y chromosome causes maleness and its absence causes femaleness?

How do we know whether or not a heteromorphic chromosome such as the Y chromosome plays a crucial role in the determination of sex?

Write a short essay that discusses sex chromosomes as they contrast with autosomes.

Distinguish between the concepts of sexual differentiation and sex determination.

Contrast the XX/XY and XX/X0 modes of sex determination.

Describe the major difference between sex determination in Drosophila and in humans.

How do mammals, including humans, solve the 'dosage problem' caused by the presence of an X and Y chromosome in one sex and two X chromosomes in the other sex?

What specific observations (evidence) support the conclusions about sex determination in Drosophila and humans?