Pattern Formation in Drosophila

Question 1

drosophila development: stage 1

Answer 1

oocyte cell is fertilized to generate the zygote

Question 2

drosophila development: stage 2 (3)

Answer 2

• following fertilization, zygotic nucleus undergoes 13 rounds of mitotic divisions without any cytokinesis (separating into two distinct cells)
• forms the syncytial blastoderm
• there are no cell membranes around each nuclei, only one around the entire embryo

Question 3

drosophila development: stage 2a

Answer 3

• after the 9th-10th round of divisions, the nuclei migrate to the periphery/border and the pole cells (germ line precursors) are formed

Question 4

drosophila development: stage 2b (2)

Answer 4

• at the end of the 13th round of division, cellularization occurs
• produces the cellular blastoderm

Question 5

drosophila development: stage 3 (2)

Answer 5

• gastrulation: more cell division and migration occurs

- produces a segmented larva with shape and form

Question 6

what are the 2 major axes in early embryogenesis

Answer 6

• anterior-posterior

- dorsal-ventral

Question 7

when are the 2 major axes of early embryogenesis established?

Answer 7

• in the oocyte

Question 8

are the developmental fates of the blastoderm fixed? why? (2)

Answer 8

• yes:
  1. anterior-posterior and dorsal-ventral axes have been set up
  2. segmentation is determined

Question 9

are there cytoplasmic determinants in the zygote

Answer 9

• yes, located at the anterior and posterior regions of the zygote

Question 10

what is the anterior portion of drosophila called?

Answer 10

• head and thorax

Question 11

what is the posterior portion of drosophila called

Answer 11

• abdomen