How Information Shapes Our World
Imagine every thought you've ever had, every memory you cherish, and every gene that makes you uniquely you—all bound by a common, invisible thread. That thread is information. We often think of information as words in a book or data on a screen, but in the world of science, information is a fundamental currency of the universe, a measurable quantity that governs everything from the spark of life to the digital revolution that defines our modern age 8 .
The entire human genome contains about 1.5 gigabytes of information—roughly the same as a typical movie file.
This article will unravel how scientists measure and study this hidden language. We'll explore the groundbreaking experiment that revealed DNA as life's information storage device and peer into the toolkit that enables today's researchers to decode the biological programs that run living organisms. Prepare to discover how the simple concept of a binary choice—yes or no, on or off—forms the basis of all complex systems, both natural and artificial.
In 1948, mathematician Claude Shannon asked a seemingly simple question: how can we accurately send messages from one point to another? His answer gave birth to information theory and ultimately paved the way for everything from the internet to genetic sequencing. Shannon introduced a radical way to think about information—not in terms of its meaning, but in terms of uncertainty reduction 8 .
Shannon created a way to measure this phenomenon using bits (binary digits)—the familiar 1s and 0s that underlie all digital computing.
What makes information theory truly revolutionary is how it transcended engineering to explain natural phenomena. Scientists began to recognize that living systems are essentially information processing systems:
Serves as a digital storage medium for biological information
Pathways act as communication networks
In the brain form complex information processing circuits
Can be understood as the editing and transmission of genetic information across generations
This paradigm shift allowed researchers to use the same mathematical tools to understand both computer networks and biological systems, leading to breakthroughs in genetics, neuroscience, and ecology.
By the early 1950s, scientists knew that genetic information was passed from generation to generation, but they didn't know which component of cells—proteins or DNA—actually carried this information. Proteins seemed more complex, while DNA appeared to be a simpler molecule. The scientific community was divided until Alfred Hershey and Martha Chase designed their now-famous 1952 experiment.
Hershey and Chase used bacteriophages (viruses that infect bacteria) as their experimental system. These viruses are remarkably simple—just protein shells containing DNA inside. The researchers exploited this simple structure in a series of elegant steps:
They prepared two sets of viruses. One set had radioactive sulfur-35 incorporated into its protein coats (since proteins contain sulfur but DNA does not). The other set had radioactive phosphorus-32 incorporated into its DNA (since DNA contains phosphorus but proteins do not).
Each set of labeled viruses was allowed to infect separate batches of bacteria.
After infection, Hershey and Chase used a laboratory blender to shear off the empty virus particles from the bacterial surfaces—a step so iconic that the experiment is often called the "blender experiment."
They then centrifuged the mixtures to separate the heavier bacteria (now in the pellet) from the lighter viral components (remaining in the supernatant).
Finally, they measured where the radioactivity ended up—inside the bacterial cells or outside with the empty viral shells.
| Material/Reagent | Function in Experiment |
|---|---|
| Bacteriophages | Simple model virus system to study genetic transmission |
| Escherichia coli bacteria | Host organism to be infected by viruses |
| Radioactive Sulfur-35 | Selective label for viral protein coats |
| Radioactive Phosphorus-32 | Selective label for viral DNA |
| Laboratory blender | Mechanical means to separate viral components |
| Centrifuge | Device to separate bacterial cells from viral debris |
The results were striking and clear. When the viruses with radioactive proteins infected bacteria, the radioactivity remained mostly in the supernatant—the protein coats never entered the bacterial cells. But when the viruses with radioactive DNA infected bacteria, the radioactivity ended up primarily in the pellet—inside the bacterial cells where new viruses were being produced.
| Experimental Group | Location of Majority Radioactivity | Conclusion |
|---|---|---|
| Sulfur-35 labeled viruses (protein tag) | Supernatant (outside bacteria) | Protein does not enter host cell during infection |
| Phosphorus-32 labeled viruses (DNA tag) | Pellet (inside bacteria) | DNA enters host cell and directs new virus production |
The DNA contained all the instructions needed to commandeer bacterial machinery and produce new virus particles. For this work, Hershey would later share the 1969 Nobel Prize in Physiology or Medicine.
The Hershey-Chase experiment came at a pivotal moment—just one year before Watson and Crick would decipher DNA's double-helix structure. It provided the crucial foundation that genetic information was stored in DNA, launching the entire field of molecular biology. Scientists could now focus their attention on understanding how this informational molecule works, leading to the cracking of the genetic code, the development of recombinant DNA technology, and eventually the Human Genome Project.
Modern laboratories studying biological information use sophisticated tools to manipulate and analyze DNA, RNA, and proteins. Here are some essential reagents that form the backbone of this research:
| Reagent/Kit | Function | Application in Research |
|---|---|---|
| DNA Polymerase | Enzyme that synthesizes new DNA strands | PCR, DNA sequencing, genetic cloning |
| Restriction Enzymes | Molecular scissors that cut DNA at specific sequences | Genetic engineering, recombinant DNA technology |
| Reverse Transcriptase | Enzyme that converts RNA into complementary DNA | Studying gene expression, RNA virus research |
| Fluorescent Dyes | Molecules that bind to nucleic acids and emit light | DNA quantification, gel visualization, sequencing |
| Agarose | Polysaccharide used to make gel matrices | DNA separation by electrophoresis |
| Nucleic Acid Extraction Kits | Reagents for purifying DNA/RNA from samples | Sample preparation for genetic analysis |
These tools have enabled scientists to move from simply observing biological information to actively reading, editing, and manipulating it—leading to revolutionary technologies like CRISPR gene editing and mRNA vaccines.
Revolutionary technology that allows precise editing of DNA sequences, opening new possibilities for treating genetic diseases.
Utilize informational molecules to instruct cells to produce proteins that trigger immune responses, as seen in COVID-19 vaccines.
The story of information continues to unfold in laboratories around the world. Today, scientists are working to decode the information processing behind consciousness, develop DNA-based data storage systems that could preserve human knowledge for millennia, and understand how information flows through ecosystems in ways that maintain planetary health.
Decoding neural information processing
Revolutionary archival technology
Understanding planetary information flows
Perhaps most remarkably, we're beginning to see that information is not just a metaphor for understanding biology but may be a fundamental property of the universe itself—some physicists now speculate that reality may literally be made of information at the most basic level.
As you go about your day, consider that every text message you send, every memory you recall, and every cell in your body participates in an ancient, continuous conversation—the exchange of information that began with the first life forms and continues to shape our future in ways we're only beginning to imagine.