It's Okay To Be Smart

$What DNA Actually Looks Like So cool! Italian scientists have “seen” a double helix (or really, a few of them) in higher resolution than ever before. But wait a sec, didn’t Rosalind Franklin do that half a century ago? Here’s the deal: DNA is smaller than the wavelength of visible light. It is, by definition, invisible to us. But by using wavelengths that are even smaller than visible light, like X-rays, we have been able to discern some of the chemical structure of DNA and other molecules. That X-ray technique gave us Rosalind Franklin’s iconic X-in-an-O image that led to the discovery of the double helix. But when we use X-rays, we are really looking at a sort of reflection pattern (or more accurately, “diffraction”) of the rays bouncing off of the atoms that make up DNA, not the DNA itself. It’s like trying to figure out the shape of a hand by looking at shadow puppets. The Italian scientists imaged DNA closer than ever before by dehydrating the double helix onto microscopic silicon pillars, and then shooting it with a beam of electrons. Where the electrons hit the DNA, we see its shape, like a normal camera, just using electrons instead of visible light. What you’re looking at above is not a single double-helix, but rather a thread made of seven double helices stacked together like threads inside yarn. We are looking at the edge of one of those helices. You can even see the fuzzy little notches of the helical turns and stacked bases! (Read more about it at The Atlantic. I originally wrote that this was a single helix, which it is not. It is a thread of seven and we are looking at the edge of one in that thread.)$

View Separately

What DNA Actually Looks Like

So cool! Italian scientists have “seen” a double helix (or really, a few of them) in higher resolution than ever before. But wait a sec, didn’t Rosalind Franklin do that half a century ago? Here’s the deal:

DNA is smaller than the wavelength of visible light. It is, by definition, invisible to us. But by using wavelengths that are even smaller than visible light, like X-rays, we have been able to discern some of the chemical structure of DNA and other molecules. That X-ray technique gave us Rosalind Franklin’s iconic X-in-an-O image that led to the discovery of the double helix.

But when we use X-rays, we are really looking at a sort of reflection pattern (or more accurately, “diffraction”) of the rays bouncing off of the atoms that make up DNA, not the DNA itself. It’s like trying to figure out the shape of a hand by looking at shadow puppets.

The Italian scientists imaged DNA closer than ever before by dehydrating the double helix onto microscopic silicon pillars, and then shooting it with a beam of electrons. Where the electrons hit the DNA, we see its shape, like a normal camera, just using electrons instead of visible light. What you’re looking at above is not a single double-helix, but rather a thread made of seven double helices stacked together like threads inside yarn. We are looking at the edge of one of those helices.

You can even see the fuzzy little notches of the helical turns and stacked bases!

(Read more about it at The Atlantic. I originally wrote that this was a single helix, which it is not. It is a thread of seven and we are looking at the edge of one in that thread.)

Source: The Atlantic