Photo 51's distinct 'X' pattern and spacing provided data to validate DNA's model

Explore a 3D model of the experimental setup Rosalind Franklin used to take Photo 51

To capture the X-ray diffraction image of DNA from the thymus of a calf, Franklin built a humidity-controlling camera to isolate the B form of DNA. The exposure lasted 60 hours and produced a cross pattern, indicating a helical structure.

X-ray data from Rosalind Franklin was key to discovering DNA’s double-helix structure

Although unpublished, the data reached James Watson and Francis Crick, who worked at another institution. Incorporating her data allowed them to validate their model of DNA, which they published without crediting her.

Rosalind Franklin was the long-overlooked contributor to discovering DNA's structure

Though James Watson, Francis Crick, and Maurice Wilkins are credited with discovering the DNA double helix, it incorporated Rosalind Franklin's unpublished data. Photo 51, her famous DNA image, took more than 100 hours to produce and a year’s worth of analysis to interpret.

Watson and Crick revealed DNA's double-helix structure using others' key findings

Their 1953 model, made from cardboard cutouts, explained how DNA stores genetic information through base pairing. Rather than experimenting and collecting their own data, they incorporated patterns and data from other scientists through trial and error.

View the model of the tobacco mosaic virus from the 1958 Brussels World's Fair

After she finished analyzing her X-ray diffraction data on DNA fibers, Rosalind Franklin explored plant virus structures. For her work on the TMV, she was invited to build this 5-foot model, modified from earlier versions made of ping pong balls and bicycle handlebar grips.

X-ray diffraction reveals atomic structures by analyzing how crystals scatter X-rays

X-ray diffraction involves rotating a crystal in an X-ray beam while a detector captures the resulting diffraction patterns, which depend on the crystal’s internal structure. The mathematical principles behind the technique won the 1915 Nobel Prize and improved crystallography.

Glowing chemicals allow scientists to read DNA like a barcode

The process of determining the order of nitrogenous bases in DNA involves first cutting the DNA into fragments, which are duplicated multiple times using bacteria. Fluorescently labeled terminator bases are added to fragments, which are sorted by length and read via laser to reconstruct the sequence.

The structure of DNA helices comes in three major varieties

The hereditary molecule can take the form of A-DNA, B-DNA, or Z-DNA based on environmental conditions such as ion concentration and humidity—a characteristic identified by Rosalind Franklin. A-DNA is the shortest and widest of the three, while Z-DNA is the longest and narrowest. B-DNA—the most common variety in living cells—is the intermediate.

Watch how DNA is packaged to a 10,000th of its original size in a cell

In humans, the 2-meter (6.56-foot) molecule wraps around spool-like proteins called histones, forming beads—nucleosomes—that fold up into fibers. These fibers—chromatin—form loops through folding that compress into larger fibers, which tightly coil together to form a chromosome.

Stacking nucleotide molecules like toy blocks helps build DNA's structure

Each nucleotide is made up of a sugar—deoxyribose—a phosphate group, and one of four bases that contain nitrogen. Like building a two-tone, spiral staircase from the ground up, nucleotides are linked one on top of another so that sugars and phosphates alternate. The twisted strands are held together by hydrogen bonds between base pairs.

Ernest Rutherford's gold foil and nitrogen experiments revealed nuclear structure

Observing high-angle deflections when alpha particles were fired at gold foil led to an atomic model with a dense, positively charged nucleus. Firing those particles at nitrogen resulted in the emission of hydrogen nuclei—protons—leading to the discovery of the subatomic particle.

Synchrotron radiation has revealed the fur color of creatures millions of years old

When electrons are accelerated in the loop, they produce intense X-rays that can reveal properties of a sample struck by them, just as X-rays can be used to show bone structure in humans. Studying the reflected light from fossils can uncover the presence of known pigmentation compounds.

Dsup slightly unwinds DNA and changes shape to better cling to the molecule

The damage suppressor protein, which is exclusively found in tardigrades, has also been modeled as coating DNA and shielding it from radiation and the toxic byproducts of radiation damage. Dsup may become a fundamental ingredient in future DNA storage technologies.

The discovery of the first extremophile and how it revolutionized DNA analysis

While investigating samples taken from within and around the hot springs at Yellowstone National Park, microbiologist Thomas Brock discovered Thermus aquaticus, a microorganism that thrived in hot water. It contained an enzyme called Taq polymerase, a critical molecule in polymerase chain reaction—a molecular photocopier that amplifies genetic signals to improve medical diagnostics.

Exploring carbon compound pore structures contributed to improved gas mask filtration

During World War II, the British Coal Utilisation Research Association sought to improve the efficiency of coal as an energy source and studied the effectiveness of charcoal filters to keep soldiers safe. Rosalind Franklin's research there formed the basis of her PhD and led to five scientific papers.

Nineteen years after its conclusion, scientists finish what the HGP started

The Human Genome Project mapped 92% of the human genome sequence upon its completion in 2003, leaving unreachable DNA regions unmapped. PacBio HiFi DNA sequencing allowed its completion 19 years later, with the additional mapping of 200 million DNA letters.

The Golden State killer case spotlights how genetic testing can affect your—and your relatives'—privacy

Police managed to use consumer DNA test results to close a case 32 years after a killer was believed to have committed at least 12 murders and 50 rapes. Their "smoking gun": They compared a DNA sample from the crime scene to genetic data relatives had shared on an open-source genealogy database. The suspect was caught after investigators explored family trees on this database and connected the dots from over 100 distant relatives who had some percentage of DNA that matched the killer. (Some users may encounter a paywall.)

View a collection of historical documents about molecular biology's history

The collection features materials related to those involved in the discovery of DNA and provides historical context for the discoveries of RNA, various viruses, and important bioproteins. The items include photographs, business correspondence, manuscripts, and scientific instruments.

Visualize how CRISPR-Cas9—a type of immune system used by single-celled organisms to attack invasive viruses—targets and makes precise changes to a gene's DNA.

NASA captures image of ghostly cosmic hand

NASA's X-ray space telescopes, Chandra and the Imaging X-ray Polarimetry Explorer, have joined forces to study a hand-shaped structure in space, revealing the magnetic field "bones" of a pulsar wind nebula. Pulsars are rotating neutron stars with strong magnetic fields, creating extreme physics conditions. The combined data from these telescopes provide insight into how pulsars inject particles into space and shape their environment, with the magnetic field playing a crucial role.

The iconic photo of the Wright brothers' first flight was the photographer’s first

Using a then-state-of-the-art Korona V, rescue member John T. Daniels was tasked with squeezing the device’s rubber bulb the moment the plane left the wooden track on the sand. The camera produced negatives on 5 by 7 sheets of glass.

The 'Penicillin Girls' made mass production possible

In Oxford during the early 1940s, six female technicians—later dubbed the “Penicillin Girls”—worked long hours tending mold cultures and extracting tiny amounts of penicillin.

Tetrachromacy allows humans to observe 10 times the normal amount of colors

Resulting from a mutation on the X chromosome, the rare genetic condition causes individuals to possess an additional type of photoreceptor cell, typically sensitive to the orange range, located between the standard red and green cones. This enables the perception of approximately 100 million colors.

The best photos of scientists at work in 2025

The winners of Nature's 2025 photo competition capture the essence of scientific fieldwork in diverse and challenging environments. From a biologist battling waves for whale research to ice core drilling in polar night conditions, this gallery details the research being each winning photo.

See the most iconic photos from four decades of LIFE magazine

The selfie camera exists thanks to Einstein's discovery of the photoelectric effect

Smartphone cameras utilize sensors such as CMOS or CCD to capture light by converting it into electrical signals through the photoelectric effect. Einstein explained this effect by demonstrating that light behaves as both particles and waves simultaneously, a discovery that earned him the Nobel Prize in physics.

Like fingerprints, brain anatomy is unique too

Researchers have discovered that a combination of experiences and genetic factors shape the anatomy of the human brain. They found even quick experiences affect the brain’s genetic makeup, which—over time—means every person develops a completely unique brain anatomy. While brain imaging could be used to identify individuals, it remains much more expensive than fingerprinting for now. Read to found out more about this study from the University of Zurich.

The first line of 'immortal' human cells, which can divide indefinitely and are used in scientific research, was nonconsensually taken from a Black woman.

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Ebola is a filovirus, meaning it resembles a thread under a microscope, though it sometimes twists and can resemble a bowl of spaghetti.

The first image of a black hole was captured by creating an Earth-sized virtual observatory from a network of eight radio telescopes.

The original copy of the Declaration of Independence is not a pristine document, and even features a smudged anonymous handprint in the bottom left corner.

The story of Dollree Mapp, whose legal challenge over her 1957 conviction for possessing "obscene material" led to a major strengthening of the Fourth Amendment

Fear or disgust related to clusters of holes and cracks, called trypophobia, may stem from evolutionary processes to help us avoid pathogens.

Objects can be 3D printed with light by projecting 2D computerized tomography (CT) scans onto rotating cylinders of resin, which solidify upon exposure.

While atoms are normally made of protons, neutrons, and electrons, exotic ones have been built with antimatter—alternate versions of normal matter that live for fractions of a second and are about a billion times as rare.

Hear 50 years of iconic hip-hop samples, the genre's foundational looped tracks

Georgia O'Keeffe's flower paintings are often assumed to be sexual, though the artist claimed she was simply interested in highlighting the beauty of flowers that most people neglect

This poison ivy knowledge quiz—accompanied by photos of the plant's varied forms—may help you identify this common rash-inducing growth.

After her fellow cult members tried to kill her with an LSD-infused hamburger, one member of the Manson Family, the murderous cult led by Charles Manson, decided to testify against the group's leader.

Sunflowers have long been a symbol of nuclear disarmament because they can extract large amounts of radioactive cesium from soil.

In 1984, Operation Smash Hit intentionally crashed a 239-ton train into a nuclear waste canister at 100 miles per hour to prove the canister's safety, which remained completely intact and lost just 0.29 of its 100 pounds of pressure.

Explore chaos in this simulation of two double pendulums, where small differences in the release angles produce wildly different outcomes.

Sony set the standard for cylinder-shaped batteries when it repurposed manufacturing equipment used to make rolls of magnetic recording tape.

See photos of Meteora, a mountainous site in central Greece, home to 14th-century monasteries perched atop soaring outcroppings.

Scientists can determine Earth's past climate conditions by analyzing air trapped in microscopic bubbles within ice cores—columns of compressed snow layers that build up over hundreds of thousands of years.

All rainbows are 'raincircles' caused by water droplets separating white sunlight into a spectrum of colors, but Earth's surface blocks the bottom half of the circle from our line of sight.

The Great Salt Lake's distinct dual coloration results from high-salinity organisms that only live in the northern portion and produce a purple protein.

When a Paris department store hesitated to sell Estée Lauder's perfume, she 'accidentally' broke a bottle, causing the smell to spread throughout the store and shoppers to start asking to buy the scent.

Legendary architect Frank Lloyd Wright designed the SC Johnson headquarters in Wisconsin, aiming to make a cathedral-like workplace