We don't even know what genes are | Philip Ball on a "new biology"

Quick Overview

Philip Ball argues against viewing living things purely as machines or as the simple readout of a genetic program, asserting that a full understanding requires examining biological systems across multiple hierarchical levels, each with its own set of rules that are only loosely dependent on the level below.

Key Points: The concept of what a gene is remains "up for grabs" because the old idea of a gene encoding one specific protein is inconsistent with modern genomic understanding. Ball argues against understanding life as a machine or as the execution of a 'genetic program,' stating that no human-built machine works like life does. Approximately 50% of human proteins are intrinsically disordered, meaning parts of their structure are "floppy and looser" and less discriminating in what they interact with, which complicates the traditional view of precise molecular recognition. This molecular 'fuzziness' or disorder seems evolutionarily useful, as more complex organisms like humans have more of it than bacteria, suggesting adaptability is necessary for evolution. Ball reframes genes not as a blueprint, but as 'part of the resources that cells use or that living organisms use in order to make themselves,' shifting agency back to the living system itself. Biological systems exhibit reciprocal determination where higher levels influence lower levels; for instance, diet affects which genes are active, demonstrating that the whole influences the parts in a literal way.

Context: Philip Ball discusses his arguments presented in his book, "How Life Works," during an interview at the How the Light Gets In event. The core discussion centers on moving beyond reductionist, mechanistic views of biology, particularly challenging the long-held concepts of genes as simple blueprints and proteins as perfectly shaped molecular machines, emphasizing the necessity of understanding biological complexity across interconnected hierarchical levels.

Detailed Analysis

Philip Ball rejects the notion that living things should be understood as machines or solely as the readout of a genetic program, noting that molecular and cell biology over the past few decades have invalidated this simplistic view. While reductionist experimentation at the molecular level is essential for understanding how molecules interact, Ball insists that a complete understanding of life requires examining all hierarchical levels in living systems, each possessing its own set of rules loosely dependent on the level beneath it. This complexity is highlighted by the discovery of intrinsically disordered proteins (IDPs); contrary to the standard model where proteins have precise shapes for specific tasks, about 50% of human proteins are floppy and 'less discriminating' in their interactions. This molecular 'fuzziness' appears evolutionarily advantageous, facilitating adaptability necessary for evolution. Furthermore, the definition of a gene is unsettled; the simple one-gene-one-protein model fails because genes are regulated in incredibly complex ways, a single gene can encode several proteins context-dependently, and vital information resides outside the gene sequence itself. Consequently, Ball prefers to view genes as resources the organism utilizes, asserting that the living system determines how its genes are used, rather than the genes dictating the entire system. He stresses that living things are characterized by mutual determination, where higher levels (like tissue or organismal state) literally determine lower-level events (like gene activation), meaning there is no priority or determinacy in any single level of the hierarchy.