We encoded computer files totalling 739 kilobytes of hard-disk storage and with an estimated Shannon information10 of 5.2 × 106 bits into a DNA code, synthesized this DNA, sequenced it and reconstructed the original files with 100% accuracy. Theoretical analysis indicates that our DNA-based storage scheme could be scaled far beyond current global information volumes and offers a realistic technology for large-scale, long-term and infrequently accessed digital archiving. In fact, current trends in technological advances are reducing DNA synthesis costs at a pace that should make our scheme cost-effective for sub-50-year archiving within a decade.

Dr. James D. Watson at Cold Spring Harbor Laboratory.

The Double Helix is a famous book. It's also an infamous one. Written by James Watson in 1968, it tells the story of how he and Francis Crick figured out the structure of DNA. The catch is that Watson chose to write that story in what was, at the time, a damn-near unprecedented way. He didn't write a history. He didn't exactly write an autobiography, either. Instead, The Double Helix is a book about history, told in story form, where everything is seen through the eyes of a single narrator — the 25-year-old James Watson.

He is not the world's most likable narrator. Nor the most reliable one. I mean that in the sense of the "unreliable narrator" from fiction. We see this world through young Watson's eyes, and his perspective isn't always accurate. The story is shaped by his prejudices and his personality, and it can't really be read as THE account of what actually happened. That's a good thing, because the choice of style allowed Watson to really capture the back-room conflict (and cooperation), and the sense of urgency, that drives scientific discovery. It's a bad thing because it's far too easy to forget that The Double Helix has more in common with Truman Capote's In Cold Blood than, say, The Decline and Fall of the Roman Empire. It's not a scholarly history. It's more like memoir crossed with narrative non-fiction. You can't walk away from it thinking that Watson's narration represents some kind of objective truth.

The new, annotated and illustrated edition of The Double Helix — published this month by Simon and Schuster — makes that fact abundantly clear. Full of photographs, letters, handwritten notes, and commentary from other people involved in the history of DNA, this edition gives you glimpses of other perspectives — of a story much bigger than the one told in The Double Helix, itself.

It also made me wonder about James Watson's reaction to documents that completely upend the story as he told it — especially documents relating to Rosalind Franklin, a scientist whose work was instrumental in deciphering DNA's structure and who is unfairly maligned in the book as a haggy, naggy, old maid caricature.

So I asked him about it.

The Curiosity rover can do a lot of things, but nobody is expecting her to find direct evidence of life on Mars. In fact, the hunt for life on the Red Planet has been a pretty stunted one. The last time we really looked was during the Viking missions, which tried to find chemical "footprints" that would exist if there had once been life on Mars, but that could end up on that planet for other reasons, as well. What we got back was a less-than-enthralling "Outlook Hazy. Try Again Later."

Ever since, we've contented ourselves with searching for indirect evidence — assessing the planet for signs that it might once have had the conditions necessary for life to happen. That's important, and it will make direct evidence of life more believable if we ever do find it, but it's not quite the same thing.

But now, DNA sequencing tools have become portable enough (and drilling technology has become powerful enough) that some scientists and Craig Ventner think we could send a probe to Mars which could find buried traces of actual DNA protected in the dirt and sequence that DNA on site.

It's also possible that life hitched a ride between Earth and Mars in their early days. Asteroid impacts have sent about a billion tonnes of rock careering between the two planets, potentially carrying DNA or its building blocks. That could mean that any genetic material on Mars is similar enough to DNA that we have a chance of finding it using standard tests.

Even if we don't, we can set up future sequencers to look for molecules that use alternative sugars or chemical letters in the genetic code. "We're not there yet, but it's not a fundamental limitation," says Chris Carr of the Massachusetts Institute of Technology, who works on the NASA-backed Search for Extraterrestrial Genomes.

Read the rest of the story at New Scientist

A study at Nanjing University in China found that ingested "microRNA" (very small pieces of ribonucleic acid, or RNA) from plants were able to survive digestion and influence the function of human cells.

Food columnist Ari Levaux has a piece digging into the implications, in The Atlantic. The basic idea: if this research stands up to the rigors of scientific scrutiny, it could prove that when we eat food, we consume not just fuel and nutrients, but information that changes us on a cellular level, and influences health.

Snip:

Monsanto's website states, "There is no need for, or value in testing the safety of GM foods in humans." This viewpoint, while good for business, is built on an understanding of genetics circa 1950. It follows what's called the "Central Dogma" (PDF) of genetics, which postulates a one-way chain of command between DNA and the cells DNA governs.

The Central Dogma resembles the process of ordering a pizza. The DNA knows what kind of pizza it wants, and orders it. The RNA is the order slip, which communicates the specifics of the pizza to the cook. The finished and delivered pizza is analogous to the protein that DNA codes for.

We've known for years that the Central Dogma, though basically correct, is overly simplistic. For example: Pieces of microRNA that don't code for anything, pizza or otherwise, can travel among cells and influence their activities in many other ways. So while the DNA is ordering pizza, it's also bombarding the pizzeria with unrelated RNA messages that can cancel a cheese delivery, pay the dishwasher nine million dollars, or email the secret sauce recipe to WikiLeaks.

Monsanto's claim that human toxicology tests are unwarranted is based on the doctrine of "substantial equivalence." This term is used around the world as the basis of regulations designed to facilitate the rapid commercialization of genetically engineered foods, by sparing them from extensive safety testing.

via The Very Real Danger of Genetically Modified Foods - The Atlantic. You'll also want to read the actual study, and make up your own mind.

Update: Here's a critical take on the linked-to Atlantic piece. Ari responds here.

(via @coopportunity)