Question 4.1

What is considered to be the fundamental difference between males and females of most organisms?

Question 4.2

How do monoecious organisms differ from dioecious organisms?

Question 4.3

Describe the XX-XO system of sex determination. In this system, which is the heterogametic sex and which is the homogametic sex?

Question 4.4

How does sex determination in the XX-XY system differ from sex determination in the ZZ-ZW system?

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Question 4.5

What is the pseudoautosomal region? How does the inheritance of traits encoded by genes in this region differ from the inheritance of other Y-linked characteristics?

Question 4.6

What is meant by genic sex determination?

Question 4.7

How does sex determination in Drosophila differ from sex determination in humans?

Question 4.8

Give the typical sex-chromosome complement found in the cells of people with Turner syndrome, with Klinefelter syndrome, and with androgen-insensitivity syndrome. What is the sex-chromosome complement of triple-X females?

Question 4.9

What characteristics are exhibited by an X-linked trait?

Question 4.10

Explain how Bridges’s study of nondisjunction in Drosophila helped prove the chromosome theory of inheritance.

Question 4.11

What characteristics are exhibited by a Y-linked trait?

Question 4.12

Explain why tortoiseshell cats are almost always female and why they have a patchy distribution of orange and black fur.

Question 4.13

What is a Barr body? How is it related to the Lyon hypothesis?