14. Genetic Control of Development

Which genes are the first genes that control patterning of the offspring during early development?

Areas with higher bicoid expression will develop into which body pattern?

Activation of the segmentation genes occurs in which of the following orders?

Which of the following HOX clusters are responsible for forming the abdominal in Drosophila development?

In this chapter, we have focused on large-scale as well as the inter- and intracellular events that take place during embryogenesis and the formation of adult structures. In particular, we discussed how the adult body plan is laid down by a cascade of gene expression, and the role of cell–cell communication in development. Based on your knowledge of these topics, answer several fundamental questions:

How do we know that eye formation in all animals is controlled by a binary switch gene?

How is positional information provided along the anterior–posterior axis in Drosophila? What are the functions of bicoid and nanos?

Early development in Drosophila is atypical in that pattern formation takes place in a syncytial blastoderm, allowing free diffusion of transcription factors between nuclei. In many other animal species, the fertilized egg is divided by cellular cleavages into a larger and larger number of smaller and smaller cells.

How must the model that describes Drosophila development be modified for describing animal species whose early development is not syncytial?

Early development in Drosophila is atypical in that pattern formation takes place in a syncytial blastoderm, allowing free diffusion of transcription factors between nuclei. In many other animal species, the fertilized egg is divided by cellular cleavages into a larger and larger number of smaller and smaller cells.

What constraints does the formation of a syncytial blastoderm impose on the mechanisms of pattern formation?