Scientists photograph DNA
DNA, the biomolecular code that props up all life, received its close-up in photos released last week.
The idea of DNA, deoxyribonucleic acid, has been tossed around since the 19th Century, when scientists began to find that DNA is the “programming” for living beings. In 1953, James Watson and Francis Crick theorized about the famous double-helix shape of DNA. Once the shape was cracked, the study of genetics took off. Since then, we’ve mapped it, cloned it and made a lot of money modifying it.
But no one had ever actually seen DNA. The miniscule particle was too difficult to catch with a camera. That all changed this year, almost 60 years after Watson and Crick made their famous corkscrew discovery.
Physics Professor Enzo di Fabrizio, working at the Magna Graecia University in Catanzaro, Italy, snapped the first photos using an electron microscope.
Watson and Crick had to discover the double-helix using indirect images of DNA, utilizing an intense process known as x-ray crystallography. According to Roland Pease of New Scientist, “This involves X-rays scattering off atoms in crystallised arrays of DNA to form a complex pattern of dots on photographic film. Interpreting the images requires complex mathematics to figure out what crystal structure could give rise to the observed patterns.”
Di Fabrizio, like much of our “see-it-to-believe-it” world, desired a more direct image. Basically, he stretched some DNA over a bed of nails and snapped away with his electron microscope.
Working at the Italian Institute of Technology in Genoa, Italy, di Fabrizio and his team took threads of DNA from a dilute solution and gently placed them among tiny pillars of silicon.
“The team developed a pattern of pillars that is extremely water-repellent, causing the moisture to evaporate quickly and leave behind strands of DNA stretched out and ready to view,” according to Pease. “The team also drilled tiny holes in the base of the nanopillar bed, through which they shone beams of electrons to make their high-resolution images. The results reveal the corkscrew thread of the DNA double helix, clearly visible.”
Di Fabrizio’s work has a whole lot more value than just the “wow!” factor. His brand new photographing technique will help researchers around the world. Scientists will be able to get direct images of how DNA interacts with other biomolecules, like RNA and certain proteins. The research could help scientists make leaps in fields as diverse as medicine and agriculture.