Technology helps decode the world in and around us

Scientists can study only the things that we can observe. We are limited to studying natural, detectable phenomena.

In the history of biology, bursts of discoveries often follow breakthroughs in technology.

The first microscopes in the 1590s permitted discovery of cells and microbes in the 1600s. Biologists described the tenets of modern cell theory by the 1850s. All organisms are made of cells. Cells are the basic unit of living things. Cells are produced by other cells.

After World War II, the 1946 Atomic Energy Act permitted the U.S. government to sell radioactive isotopes, produced in nuclear reactors, for research and medical treatments. Using these atomic energy “byproducts,” biologists identified DNA as the genetic material in 1952. They described the structure of DNA in 1953, and explained how DNA replicates in 1958.

Those dominoes of DNA discovery that began falling in the middle of the last century led to the release of the complete human genome sequence at the start of this century. Along the way, we invented technologies to automate gene sequencing. And what started as a slow, laborious, expensive process has become a rapid, easy, inexpensive way to map every gene of any organism that a biologist studies.

At the start of the DNA age, biologists identified a species of interest and acquired a specimen. They then extracted, sequenced and compared its genes with other species.

Modern, automated gene sequencing reverses this process.

With high-throughput DNA sequencers, biologists identify all of the genes in a sample of ocean water or human gut contents. They use computer programs to assemble the most likely community of microorganisms in the sample. They use gene sequences to identify species present in a microbiome, all of the microbes in the sample.

Invention of microscopes led to the discovery of cells and microorganisms. Invention of high-throughput gene sequencing techniques has led to the discovery of microbiomes around us, on us and in us.

Biologists have just begun to discover the extent and impact of microbiomes. Consider these microbiome discoveries published in the past two months:

■ Pregnant mothers with decreased vaginal microbiome diversity experience more preterm births.

■ Characterizing the gut microbiome of patients with inflammatory bowel disease can advise effective therapies to treat the condition.

■ Patients with an imbalanced gut microbiome are more likely to have scleroderma, an autoimmune disease that hardens and scars connective tissue.

■ Composition of a person’s microbiome might influence his or her risk for obesity and nonalcoholic fatty liver disease. Characterization of the gut microbiome might provide early warning of the disease.

■ Composition of the microbiome in hair follicles might influence the development of acne in patients.

What you don’t see, you can’t understand. As individual organisms, we are living ecological communities with healthy and diverse — or not— microbiomes on us and in us. We interact with and depend on individuals of other species to feed us and provide us other ecological services. Each of those individuals has a microbiome.

You can’t tell the players without a program. We’re in the earliest stages of writing programs to identify players in microbiomes on which we depend.