Chapter 19, Problem 3Q

Summary Introduction

To review:

The possibility that may occur if hairball were expressed in other thoracic segments in both species 1 and 2. Also, it is to be assessed whether this is an example of heterometry, heterotrophy, or heterochrony.

Introduction:

The bristles in Drosophila do not grow on their other two thoracic segments. Hairball is also not expressed at high levels in these segments. During development, a different species 3 has hairs on other thoracic segments and hairball is expressed in these segments of this species.

Heterometery is referred to as the change in the amount of gene expression during the developmental stages of an organism. Heterotrophy is termed as the evolutionary change in the spatial patterning of development. Heterochrony is defined as the change in gene expression timings and developmental rates of an organism.