Question 1
How do segment polarity genes relate to pair-rule genes?Question 2
Molecular/structural orientations (gradients) in an egg are thought to play a significant role in development. What is the origin of such gradients? What evidence indicates that the maternal genotype is involved in providing such gradients?Answer 1
Segment polarity genes are controlled by transcription factors encoded by the pair-rule genes.Answer 2
In examples of maternal effects, the mother's genotype establishes the early body plan. During formation of any egg, nutritional, regulatory, and informational molecules (RNAs) are placed in appropriate positions for development of the embryo. Many maternal-effect genes have been identified in Drosophila.