The Smell of Evolution

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Evolution drives relentlessly forward, leaving behind a messy wake. One of the best places to survey its sloppy creativity is inside your nose.

When you smell a lily or a cigar or a jug of spoiled milk, you are grabbing their molecules out of an ocean of air. You have exposed nerve endings dangling deep inside your nostrils, each of which is studded with proteins called olfactory receptors. Each neuron is covered in one type of receptor, the shape of which allows it to grab tightly onto certain odor molecules and weakly to others, while letting many others drift by.

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Vitamins’ Old, Old Edge

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The New York Times, December 9, 2013

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In 1602, a Spanish fleet was sailing up the Pacific coast of Mexico when the crew became deathly ill. “The first symptom is pain in the whole body that makes it sensitive to touch,” wrote Antonio de la Ascensión, a priest on the expedition. “Purple spots begin to cover the body, especially from the waist down; then the gums become so swollen that the teeth cannot be brought together, and they can only drink, and finally they die all of a sudden, while talking.”

The crew was suffering from scurvy, a disease that was then both bitterly familiar and deeply mysterious. No one knew why it struck sailors or how to cure it.

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Vitamins: The First Four Billion Years

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Vitamins are one of those features of life that we take for granted. For some odd reason, we must obtain trace amounts of a dozen or so tiny molecules, or we will get very, very sick. To understand why this is so, you have to look back at the history of vitamins. And that history stretches back pretty much to the origin of life, a history whose traces we can see in our own DNA, and one that has shaped the balance of nature. For more, check out my feature in tomorrow’s New York Times (I’ll have more to add in my “Matter” column for the Times on Thursday).

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Baffling 400,000-Year-Old Clue to Human Origins

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The New York Times, December 4, 2013

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Scientists have found the oldest DNA evidence yet of humans’ biological history. But instead of neatly clarifying human evolution, the finding is adding new mysteries.

In a paper in the journal Nature, scientists reported Wednesday that they had retrieved ancient human DNA from a fossil dating back about 400,000 years, shattering the previous record of 100,000 years.

The fossil, a thigh bone found in Spain, had previously seemed to many experts to belong to a forerunner of Neanderthals. But its DNA tells a very different story.

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