Lecture 25 - Developmental Genetics

Question 1

What are egg-polarity genes, segmentation genes, and homeotic genes?

L25 S18

Answer 1

Egg-polarity genes:
-establishes main body axes

Segmentation genes:
-determines number and polarity of body segments

Homeotic genes:
-establishes identify of each segment

Question 2

What is a morphogen?

L25 S19

Answer 2

Protein that affects the fate of surrounding region through a concentration gradient

Question 3

What are Homeobox genes?

Answer 3

Contains Homeobox region which consists of ~180 bases

Encodes protein with a homeobox region that can bind DNA and plays a regulatory role in identifying body regions

E.g. hox gene
-located in the same order on the chromosome as their order of expression

Question 4

Mutations in homeotic genes often cause:

L25 S41

A. the deletion of segments.
B. the absence of structures.
C. too many segments.
D. structures to appear in the wrong places.

Answer 4

D. structures to appear in the wrong places.