From Fearsome Predator to Man’s Best Friend

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The New York Times, May 16, 2013

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Imagine a wolf catching a Frisbee a dozen times in a row, or leading police officers to a stash of cocaine, or just sleeping peacefully next to you on your couch. It’s a stretch, to say the least. Dogs may have evolved from wolves, but the minds of the two canines are profoundly different.

Dog brains, as I wrote last month in The New York Times, have become exquisitely tuned to our own. Scientists are now zeroing in on some of the genes that were crucial to the rewiring of dog brains.

Their results are fascinating, and not only because they can help us understand how dogs turned into man’s best friend.

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How To Evolve a Dog’s Brain (And A Human One, While We’re At It)

Posted on by Matt Kristoffersen

It’s Thursday, and that means that I’m publishing my next piece for Matter, my weekly column for the New York Times. Today, I take a look at dogs. Last month I wrote in the Times about cognitive scientists playing games with dogs to probe their behavior. But that’s just part of the story of canine research these days. There are also geneticists out there looking at the same question from a different perspective. They want to find the genes that evolved over the past 30,000 years or so to turn the brain of a wolf into the brain of a dog. The answers are now starting to emerge, and they’re fascinating. They may, in fact, tell us a lot about how we became humans. Check it out!

Originally published May 16, 2013. Copyright 2013 Carl Zimmer.

Tracing Breast Cancer’s History

Posted on by Matt Kristoffersen

In today’s New York Times, the actress Angelina Jolie published a remarkably forthcoming op-ed about getting a double mastectomy. Jolie carries a variant of a gene called BRCA1 that makes women highly likely to develop breast and ovarian cancer. Her mother, who also carried the variant, died of ovarian cancer at age 56. Like a number of other women with her condition, Jolie decided to get a mastectomy as a preventative measure.

A number of studies have shown that bilateral risk-reducing mastectomies (the official term) do indeed reduce the risk of breast cancer in women with the BRCA1 mutation. In a study published last month in Annals of Oncology, a team of Dutch medical researchers tracked 570 women with BRCA1 (or a mutation in the related gene BRCA2). At the start of the study, all the women were healthy; 212 of them later chose to get risk-reducing mastectomies. Over the next few years, the researchers followed their progress. Sixteen percent of the women who didn’t get risk-reducing mastectomies developed breast cancer; of the women who went Jolie’s route, none did.

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The Lurker: How A Virus Hid In Our Genome For Six Million Years

Posted on by Matt Kristoffersen

In the mid-2000s, David Markovitz, a scientist at the University of Michigan, and his colleagues took a look at the blood of people infected with HIV. Human immunodeficiency viruses kill their hosts by exhausting the immune system, allowing all sorts of pathogens to sweep into their host’s body. So it wasn’t a huge surprise for Markovitz and his colleagues to find other viruses in the blood of the HIV patients. What was surprising was where those other viruses had come from: from within the patients’ own DNA.

HIV belongs to a class of viruses called retroviruses. They all share three genes in common. One, called gag, gives rise to the inner shell where the virus’s genes are stored. Another, called env, makes knobs on the outer surface of the virus, that allow it to latch onto cells and invade them. And a third, called pol, makes an enzyme that inserts the virus’s genes into its host cell’s DNA.

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