Chapter 15 Biological Inferences

Abstract

When we try to pick out anything by itself, we find it hitched to everything else in the universe.

John Muir

This book is devoted to a description of a single biological species called λ. In Chapter 1 Hershey and I have suggested technical reasons that have favored λ for intensive study. One can expect to learn so much about no more than a few of the millions of species that make up the biological universe.

To draw inferences about the biological universe from observations on λ is risky, if not foolhardy. To some extent we can expect each species to display unique solutions, even for general biological problems. I go to some lengths in this chapter to illustrate ways in which solutions found by λ are indeed special ones. “There can be no formula for serendipity” (Wright, 1959).

This chapter will focus on two forms of biological organization. One, physiological organization, deals with the temporal and spatial coordination involved in λ growth. The other, genetic organization, is the arrangement of genetic elements in the λ chromosome. This structure is viewed in terms of the physiological organization of λ and in terms of the pathways of natural selection along which the λ genome evolves.

PHYSIOLOGICAL ORGANIZATION
The Immune and the Derepressed Phases
Elements in the immunity region of λ maintain the lysogenic state. Genes situated in other regions of the λ chromosone act at one or another stage in productive growth. These two sets of genes are mutually exclusive in...