Every year at Sweet Briar College there’s an event called Briar Bowl in which a bunch of teams of nerds students with one faculty member each get together and compete by answering trivia. It’s loads of fun. There’s the opportunity for bragging rights hanging out with friends and faculty. I hope other schools host something similar. The questions are totally random: everything from pop-culture (author of 50 Shades of Gray) to mathematics (if an object is traveling at 5ft/s, how far has it gone in an hour?). The Dean reads the questions, and the students all scribble their answers in a mad flurry. When the science questions come up I get handed the pen whether I have a clue or not.

Once, I actually did know the answer. The particular factoid in question had been drilled into my head over and over ever since pre-biology in seventh grade. Question: What two scientists won the 1962 Nobel Prize for Physiology/Medicine for solving the conundrum of DNA’s structure? Answer: Francis Crick and James Watson (and technically, Maurice Wilkins).

Helix

Single Helix

Disclaimer: I’m not a biologist. Recently, I ended up learning a few things about DNA as a result of fellow Sweet Briar student, Samantha Meiser’s research. Before I get into that, I’d like to take a moment to recognize Rosalind Franklin, whose research on the structure of DNA was somewhat undermined by the official winners of the Nobel Prize. Rosalind Franklin took groundbreaking X-ray photographs of DNA molecules which revealed their helical (spiral) structure. Although Franklin had died by the time the award was given, it’s unlikely that her efforts would have been noted anyway, given the attitudes of those who received the prize. Francis Crick once admitted “I’m afraid we always used to adopt — let’s say, a patronizing attitude towards her” (1). That’s not to say that Crick, Watson, and Wilkins didn’t do valuable research. They did. But so did Franklin. Read this article for more of the story.

Anyway, some research has been done since the ’60’s which reveals that the double helix isn’t the only structure for DNA. What Watson and Crick did was connect the single helix’s from Franklin’s photographs, revealing that the actual structure is a double helix. Here’s a basic run down of this DNA (deoxyribonucleic acid) structure: the “double helix” is two long chains twisted around each other (like a swirling ladder). The chains are made of a few types of molecules, notably nucleotides. Nucleotides in DNA make up nucleic acids which fit together in neat pairs when the helices are fitted together. Below is a video for kids that actually explains it pretty well, and it’s only like two minutes long:

So, just to throw a curve ball at you, there are actually other structures of DNA, like the g-quadruplex (this is what Samantha researched). G-quadruplex DNA is square-shaped, and consists of four of the same nucleotides (four guanines). Recent research has shown that this form of DNA is likely to occur naturally in some cells, and studying it may be valuable in understanding how cancer grows and spreads (2). It is believed that g-quadruplex DNA is important in the process of DNA replication (definitely check that link out). Therefore, if something goes wrong with the g-quadruplex structure, there could be serious negative impacts on the production of healthy DNA molecules (3).

File:G-quadruplex.svg

G-Quadruplex Molecule Structure (NOT a double-helix)

I’ve been under the impression that the double helix is the only structure for DNA. One of the reasons I choose to study science is that it’s always changing and advancing. You never know what you might learn to be true or untrue. In organic chemistry, there were numerous occasions in which the best the textbook could do was to say “it is believed that….”

What I’m learning today might be proven totally wrong in the next few years, but that’s okay. Science has to be adaptable and open to new possibilities, possibilities that we haven’t even imagined yet.

Thanks for reading : )

-Ashley

 

(1) http://www.pbs.org/wgbh/aso/databank/entries/do53dn.html

(2) http://www.scientificamerican.com/article.cfm?id=four-strand-dna-structure-found-cells

(3) http://bioinformatics.oxfordjournals.org/content/25/12/i374.full


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