Few genes can be said to function "on their own". Rather, most
genes can be ascribed a function primarily in the sense that the
activities of their product are required for the function of
some larger network of interactions among several gene products
to produce some sort of higher-order behavior. It is the
function and behavior of networks that biologists usually seek
to understand. For example, the proteins that regulate cell
cycle progression are endowed with various activities (kinases,
phosphatases, etc.). Rather than explain their function, much
less cell cycle control, by listing the various targets of those
activities, biologists are usually after something like an
explanation of how all those activities conspire to produce a
biochemical oscillator, and how they maintain coordination
between the various metabolic and mechano-chemical processes
that make up cell growth and division. Most gene networks are
complicated enough that it is a major challenge for humans to
use verbal reasoning to envision ho