Mindframe

Even if you from time to time think about your neurons, those little chemical-electrical switches that dictate your mental and physical activity, you probably don't give much thought to your transposons. And yet transposons don't just play a crucial role in neural application; in a very real sense, they define who you are. A transposon is a fragment of DNA that inserts itself into another cell. Research suggests that about half our DNA sequence is made up of these fragments, these interlopers. In the cells of, say, your lungs, heart, or kidneys, transposons have no real effect. They don't behave like viruses, which sneak into cells and multiply like crazy. They're more like very mellow hitchhikers: once they've found their way in, they're usually content to fall asleep and enjoy the ride. The exception is the brain. Once transposons get inside neurons, they can alter the very nature of the cell. It's like a troupe of improv actors that show up unexp...

Located in the mountains of southwestern Siberia, the Denisova Cave takes its name from a Russian hermit named Denis, rumored to have lived there in the 18th century. When some intriguing bones were discovered in this cavern, the moniker derived from his long-dead hermit would gain a new use: as a shorthand for a stunning discovery about the world of our early human ancestors. In 2008, Russian researchers discovered the finger bone of a young humanoid female. It was the wrong shape to come from a Homo sapien, but when scientists sequenced the DNA, it didn't seem to belong to a Neanderthal, either. They had found what appears to be an entirely separate group of early hominids whose time on this planet briefly overlapped with ours. A genetic cousin to us, and a genetic sister to the Neanderthal. They had found the Denisovans. Where early Homo sapiens and Neanderthals split into separate species some 440,000 years ago, Denisovans didn't branch off from the Neanderthals unti...

40,000 years ago, the story goes, there were two kinds of early humanoids roaming the land. There were the Homo Sapiens, our noble early ancestors. Then there were the savage, brutish knuckledraggers called the Neanderthal, destined to die out, unable to compete with their more enlightened Homo Sapien cousins. Turns out the truth is more complicated--and much more interesting. Check your family tree: if you're of European or Asian descent, there is a possibility that you've got a trace of Neanderthal in your past. Using 44,000-year-old fossil bone fragments found in a cave in Croatia, scientists at Max Planck Institute were able to extract enough DNA to sequence the Neanderthal genome. (Editors note: anyone else sensing a Jurassic Park spin-off? Just me? Okay.) Based on comparing the sequencing with modern humans, some scientists suggest that between 1% and 4% of modern Asian and European DNA might have come directly from Neanderthals. So far, the same can't be ...