Temporal Pattern of Bristle Development on Drosophila melanogaster Sternites

Abstract

Bristle development in D. melanogaster can be prevented with X-rays administered prior to the final differentiative divisions of bristle-committed epidermal cells. The epidermal cells are radiationinsensitive if the same dose is given after cell division. By subjecting variously aged early pupae to X-radiation and subsequently scoring bristle numbers in adults, a temporal pattern of radiation insensitivity was established on the abdominal sternites. The pattern is a simple gradient extending anteriorly and medially from the posterior lateral sternite ·corners'. The possible significance of this to the origin of bristle spatial patterns is discussed.