The history of African-Americans has been shaped in part by two great journeys.

The first brought hundreds of thousands of Africans to the southern United States as slaves. The second, the Great Migration, began around 1910 and sent six million African-Americans from the South to New York, Chicago and other cities across the country.

In a study published on Friday, a team of geneticists sought evidence for this history in the DNA of living African-Americans. The findings, published in PLOS Genetics, provide a map of African-American genetic diversity, shedding light on both their history and their health.

Continue reading “Tales of African-American History Found in DNA” →

COPENHAGEN — As a boy growing up in Denmark, Eske Willerslev could not wait to leave Gentofte, his suburban hometown. As soon as he was old enough, he would strike out for the Arctic wilderness.

His twin brother, Rane, shared his obsession. On vacations, they retreated to the woods to teach themselves survival skills. Their first journey would be to Siberia, the Willerslev twins decided. They would make contact with a mysterious group of people called the Yukaghir, who supposedly lived on nothing but elk and moose.

When the Willerslev twins reached 18, they made good on their promise. They were soon paddling a canoe up remote Siberian rivers.

Continue reading “Eske Willerslev Is Rewriting History With DNA” →

Animal migrations combine staggering endurance and exquisite timing.

Consider the odyssey of a bird known as the red knot. Each spring, flocks of the intrepid shorebirds fly up to 9,300 miles from the tropics to the Arctic. As the snow melts, they mate and produce a new generation of chicks. The chicks gorge themselves on insects, and then all the red knots head back south.

“They are there less than two months,” said Jan A. van Gils, an ecologist at the Royal Netherlands Institute for Sea Research. “It’s a very tight schedule.”

Continue reading “Climate Change and the Case of the Shrinking Red Knots” →

If there is ever a contest for Least Appreciated Creature on Earth, first prize should go to a microbe called Wolbachia.

The bacterium infects millions of invertebrate species, including spiders, shrimps and parasitic worms, as well as 60 percent of all insect species. Once in residence, Wolbachia co-opts its hosts’ reproductive machinery and often greedily shields them from a variety of competing infections.

Ever since the Zika outbreak began in Brazil last year, scientists have suspected that Wolbachia might protect mosquitoes from the virus.

Continue reading “Bacteria-Infected Mosquitoes Could Slow Spread of Zika Virus” →

The Channel Islands, off the coast of Southern California, are a natural laboratory for a particularly adorable experiment in evolution.

A unique species called the island fox has lived there for several thousand years, their bodies shrinking over the generations until now each is smaller than a house cat. Adult island foxes weigh as little as 2.35 pounds.

Now a team of scientists has discovered another way in which island foxes are extraordinary: Genetically, they are nearly identical to one another. In fact, a fox community on one island has set a record for the least genetic variation in a sexually reproducing species.

Continue reading “Foxes That Endure Despite a Lack of Genetic Diversity” →