Comprehension Questions

Section 8.1

Question 8.1

List the different types of chromosome mutations and define each one.

Section 8.2

Question 8.2

Why do extra copies of genes sometimes cause drastic phenotypic effects?

Question 8.3

Draw a pair of chromosomes as they would appear during synapsis in prophase I of meiosis in an individual heterozygous for a chromosome duplication.

Question 8.4

What is haploinsufficiency?

Question 8.5

What is the difference between a paracentric and a pericentric inversion?

Question 8.6

How can inversions in which no genetic information is lost or gained cause phenotypic effects?

Question 8.7

Explain, with the aid of a drawing, how a dicentric bridge is produced when crossing over takes place in an individual heterozygous for a paracentric inversion.

Question 8.8

Explain why recombination is suppressed in individuals heterozygous for paracentric and pericentric inversions.

Question 8.9

How do translocations in which no genetic information is lost or gained produce phenotypic effects?

Question 8.10

Sketch the chromosome pairing and the different segregation patterns that can arise in an individual heterozygous for a reciprocal translocation.

Question 8.11

What is a Robertsonian translocation?

Section 8.3

Question 8.12

List four major types of aneuploidy.

Question 8.13

What is the difference between primary Down syndrome and familial Down syndrome? How does each type arise?

Question 8.14

What is uniparental disomy and how does it arise?

Question 8.15

What is mosaicism and how does it arise?

Section 8.4

Question 8.16

What is the difference between autopolyploidy and allopolyploidy? How does each arise?

Question 8.17

Explain why autopolyploids are usually sterile, whereas allopolyploids are often fertile.

For more questions that test your comprehension of the key chapter concepts, go to for this chapter.