A metabolome is a detailed breakdown of signaling chemicals, metabolites, hormones, and similar structures found in an organism. Some of these are produced naturally, others through the metabolism of various ingested foods and drugs. Over the course of its lifetime, an organism's collection of chemical compounds will change. It is possible to take a snapshot in time to see what an organism contained and produced at one point, but this will change from moment to moment.
The study of the human metabolome is a topic of particular interest. Medical testing often relies on metabolites for diagnostic purposes. A doctor can check for the presence or absence of compounds to rule diseases in or out, or to see how well a patient responds to medications. Only a fraction is identifiable with basic medical testing. Expanding the number of metabolites doctors could test for would create more opportunities for accurate diagnosis and testing of patients.
This provides a unique opportunity to study interactions between genetics and environment. The genome codes for the production of a number of compounds like hormones, enzymes, and so forth. Errors can create problems like deficiencies or defective chemicals. Meanwhile, the environment also has an impact on a person's metabolome; what the person eats, drinks, and is otherwise exposed to will change his metabolome and create a different set of signature chemicals.
Researchers with an interest in how environment and genetics can interplay may study the metabolome to look at the intersection of these topics. They can look at the way environmental influences silence genes or turn them on, for example. It can also provide clues into how organisms deal with changing environmental circumstances, and what happens when organisms are exposed to toxins. The metabolome contains a variety of chemicals the body uses for life, from molecules for energy to power cells to signaling hormones that trigger fertility and allow for reproduction.
A Canadian research team was the first to develop a rough sequence of the human metabolome. This work is challenging, as samples from different areas of the body will contain different chemicals, and these can also shift over time. Simply sequencing the compounds found in liver cells, for example, would yield a different picture than studying tissue and fluids from other parts of the body, as many parts of the metabolome are very location-specific. Some signaling cells are found only in specific regions, while specific metabolites may be in some areas of the body, but not others. Successful sequencing requires detailed and meticulous sampling.