To test a hypothesis, scientific techniques must adequately distinguish between the metrics of a hypothesis (‘signal’) and information that is unrelated to the hypothesis (‘noise’). They must have contrast.
In biochemistry, where molecules are routinely defined at the atomic level, such contrast is commonplace. Unfortunately, the environment in which biochemistry operates — the cell — is less granular. Cells are chaotic snake-pits of interweaving biochemistry. This complexity can make studying cells a rather soft, fuzzy, low-contrast endeavor.
Fortunately, for scientists (and biology in general), the more easily-defined world of biochemistry underpins cellular chaos. Despite their complex environment, cellular molecules interact specifically and for the most part, order prevails. As a result, researchers can use tools from the high-contrast domain of biochemistry to study the complex domain of cell biology.
In his book “The Nature of Technology”, W. Brian Arthur suggests technical innovation occurs when a set of tools from one domain are used to solve a problem in another domain. Innovation is the “re-domaining” of a technology. As the ‘new’ tools must already exist in a domain external to the problem, innovation requires the cross-fertilization of different technical domains.
Modern labs are littered with the products of such cross-domain innovation. For example, basic immunology knowledge is routinely exploited (through the medium of antibodies) to investigate the expression and location of proteins in cells (see western blots and immunofluorescence). Research into the thermodynamics of nucleic acid hydrogen bonding and thermostable DNA polymerases revolutionised the way genes are isolated (see PCR). Instruments initially designed for measuring the mass and charge of chemical ions (mass spectrometers) now empower the way we understand cell signaling (see phosphoproteomics).
In all cases, technical knowledge from one domain is applied to solve a problem in another domain.
A fresh example comes from from Alice Ting’s group as reported last week in Science. First the authors engineered a new enzyme to specifically label proteins in the mitochondria (and not anywhere else in the cell). They then used this specific labelling to separate mitochondrial proteins from the noisy snake-pit of other cellular proteins. Once isolated, the authors could then measure the mitochondrial proteins with unparalleled accuracy using mass-spectrometry.
By cross-fertilizing the domain of recombinant enzyme engineering with contemporary proteomics, this technique can record detailed measurements of something surrounded by noise.
High-contrast indeed.