The New York Times, April 12, 2018

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Of all the plants that humanity has turned into crops, none is more puzzling than the sweet potato. Indigenous people of Central and South America grew it on farms for generations, and Europeans discovered it when Christopher Columbus arrived in the Caribbean.

In the 18th century, however, Captain Cook stumbled across sweet potatoes again — over 4,000 miles away, on remote Polynesian islands. European explorers later found them elsewhere in the Pacific, from Hawaii to New Guinea.

The distribution of the plant baffled scientists. How could sweet potatoes arise from a wild ancestor and then wind up scattered across such a wide range? Was it possible that unknown explorers carried it from South America to countless Pacific islands?

Continue reading “All by Itself, the Humble Sweet Potato Colonized the World”

The New York Times, March 29, 2018

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In 2013, two biologists named Jamie Voyles and Corinne L. Richards-Zawacki spent weeks slogging up and down mountainsides in Panama. “We were bug-bitten and beat up,” recalled Dr. Voyles, now an assistant professor at the University of Nevada, Reno.

Near the end of their trek, they came to a stop. In front of them sat the object of their quest: a single gold-and-black frog.

“I can’t tell you what that moment was like,” Dr. Voyles said.

She had feared that variable harlequin frogs had disappeared entirely from Panama. As recently as the early 2000s, they had been easy to find in the country’s high-altitude forests.

Continue reading “A Few Species of Frogs That Vanished May Be on the Rebound”

The New York Times, March 28, 2018

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Days after researchers announced that a tiny mummy once rumored to be an alien was actually a human infant, Chilean scientists condemned the new study as unethical and their government began an investigation into grave robbing.

The Chilean National Monuments Council, a government agency, said in an email Tuesday that it had initiated an inquiry into whether the little girl’s remains were illegally exhumed in 2003 and smuggled out of the country. The council has turned over its records to the Public Ministry of Chile in response to the outcry from Chilean researchers. They contended that the grave site was plundered and the mummified skeleton was stolen, violating the country’s laws.

“It’s offensive for the girl, for her family, and for the heritage of Chile,” said Francisca Santana-Sagredo, a biological anthropologist at the University of Antofagasta and the University of Oxford.

In a telephone interview, two authors of the new study, Dr. Garry P. Nolan, an immunologist at Stanford University, and Atul Butte of the University of California, San Francisco, defended the ethics of their research.

Continue reading “Chile and Its Scientists Protest Research on Tiny Mummy”

The New York Times, March 20, 2018

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BOSTON — David Reich wore a hooded, white suit, cream-colored clogs, and a blue surgical mask. Only his eyes were visible as he inspected the bone fragments on the counter.

Dr. Reich, a geneticist at Harvard Medical School, pointed out a strawberry-sized chunk: “This is from a 4,000-year-old site in Central Asia — from Uzbekistan, I think.”

He moved down the row. “This is a 2,500-year-old sample from a site in Britain. This is Bronze Age Russian, and these are Arabian samples. These people would have never met each other in time or space.”

Dr. Reich hopes that his team of scientists and technicians can find DNA in these bones. Odds are good that they will.

In less than three years, Dr. Reich’s laboratory has published DNA from the genomes of 938 ancient humans — more than all other research teams working in this field combined. The work in his lab has reshaped our understanding of human prehistory.

Continue reading “David Reich Unearths Human History Etched in Bone”

The New York Times, March 15, 2018

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Gregor Mendel discovered fundamental rules of genetics by raising pea plants. He realized that hidden factors — we now know them to be genes — were passed down from parents to offspring.

It wasn’t until the early 1900s, long after Mendel’s death, that doctors discovered that humans weren’t so very different. Some diseases, it turns out, are inherited — they’re Mendelian.

Today, scientists have identified over 7,000 Mendelian diseases, and many are discovered with screenings of children and adults. But a new study suggests that many disorders go undetected.

Continue reading “What’s Behind Many Mystery Ailments? Genetic Mutations, Study Finds”