Darwin's Doubt: The Explosive Origin of Animal Life and the Case for Intelligent Design

by Stephen C. Meyer

For example, early embryo development in the fruit fly Drosophila melanogaster requires the regulatory molecules Bicoid and Nanos (among others). The former is required for anterior (head) development, and the latter is required for posterior (tail) development.19 In the early stages of embryological development, nurse cells pump Bicoid and Nanos RNAs into the egg. (Nurse cells provide the cell that will become the egg—known as the oocyte—and the embryo with maternally encoded messenger RNAs and proteins.) Cytoskeletal arrays then transport these RNAs through the oocyte, where they become attached to specified targets on the inner surface of the egg.20 Once in their proper place—but only then—Bicoid and Nanos play critical roles in organizing the head-to-tail axis of the developing fruit fly. They do this by forming two gradients (or differential concentrations), one with Bicoid protein most concentrated at the anterior end and another with Nanos protein most concentrated at the posterior end. Insofar as both of these molecules are RNAs—that is, gene products—genetic information plays an important role in this process. Even so, the information contained in the bicoid and nanos genes does not by itself ensure the proper function of the RNAs and proteins for which the genes code. Instead, preexisting membrane targets, already positioned on the inside surface of the egg cell, determine where these molecules will attach and how they will function. These membrane targets provid...

How complex even for a simple thing.