Week 4

Question 1

morphogenesis

Answer 1

morpho - form

genesis - birth/beginning

Question 2

modelling of developmental patterns

Answer 2

reaction diffusion model

Question 3

Prediction of our model

Answer 3

hierarchical pattern generators should be more robust than sequential pattern generators

• drosophila forms its segments using hierarchical system and always produces same number of segments

Question 4

conclusions from expirmental work of klaus sander

Answer 4

• cytoplasm sampled from different regions of the egg had different biological properties
• results implied existence of movable molecular structures, or determinants, able to transmit information to egg

Question 5

Experimental embryology experiments

Answer 5

• Focus on simple patterns along the Antero-Posterior (A-P) axis
• The cytoplasm sampled from different regions of the egg had
  different biological properties
• Results implied the existence of movable molecular structures
  or determinants (i.e., ‘polarity determinants’) able to transmit information to the egg, indicating where different structures
  should or should not form

Question 6

developmental genetics approach

Answer 6

1. search for molecular controllers of devlopment
2. classifying genes and developmental effects
3. limits of developmental genetics approach

Question 7

maternal effect mutations

Answer 7

• anterior and posterior systems

depend on localised RN or protein products maternally encoded and localised in egg by mother during oogenesis

• terminal and dorso/ventral systems

do not depend on localised products inside the egg

Question 8

The phenotypic classes of zygotic mutants

Answer 8

specific genes are needed to build pattern in distinct
regions of the embryo

• During segmentation a pattern with double-segment periodicityis generated first (e.g. even-skipped)
• Different genes are necessary for the final development of
  pattern within parts of each segment