Q7 - Developmental Genetics II

Question 1

What are the two broad groups of genes that have an effect on early embryo development in Drosophila?

Answer 1

Maternal effect genes and zygotic genes

Question 2

Describe the maternal effect genes that impact on early Drosophila development

Answer 2

Genes that function within the mother to determine the embryo’s polarity and body plan

Question 3

Describe the zygotic genes that impact on early Drosophila development

Answer 3

Genes that function in the embryo to build upon the basic layout provided by the maternal effect genes

Question 4

Why can early Drosophila segmentation be described as hierarchical?

Answer 4

They are expressed in stages, where the products of one regulate the expression of the next

Question 5

What are the two types of zygotic genes that impact early Drosophila development?

Answer 5

Segmentation genes and homeotic genes

Question 6

What are the maternal effect genes in early Drosophila development?

Answer 6

Anterior, posterior and terminal genes

Question 7

What do the anterior maternal effect genes do in early Drosophila development

Answer 7

Bicoid products act as transcription factors for genes that determine the head and thorax

Question 8

What do the posterior maternal effect genes do in early Drosophila development

Answer 8

Nanos products repress bicoid translation in the posterior region and lead to the generation of abdominal segments

Question 9

What do the terminal maternal effect genes do in early Drosophila development

Answer 9

Determine the acron (anterior tip) and telson (posterior tip)

Question 10

What type of gradient do the maternal effect genes establish in the developing Drosophila embryo?

Answer 10

Anterior-posterior bicoid gradient and posterior-anterior nanos gradient

Question 11

What are the three types of zygotic segmentation genes (in the correct order) that affect Drosophila segmentation?

Answer 11

Gap, pair-rule and segment polarity genes

Question 12

What are some of the zygotic gap genes? What do they do?

Answer 12

Hunchback and Kruppel genes - separate the embryo into regions along the anterior-posterior axis

Question 13

What are some of the zygotic pair-rule genes? What do they do?

Answer 13

Even-skipped and Fushi-tarazu - define the regions made by gap genes into 7 alternate stripes (15 subunits)

Question 14

What are some of the zygotic segment-polarity genes? What do they do?

Answer 14

Engrailed and wingless genes - establish the borders of segments and parasegments