Multiple sclerosis, an autoimmune disease that affects 2.9 million people, presents a biological puzzle.

Many researchers suspect that the disease is triggered by a virus, known as Epstein-Barr, which causes the immune system to attack the nerves and can leave patients struggling to walk or talk. But the virus can’t be the whole story, since nearly everyone is infected with it at some point in life.

A new study found a possible solution to this paradox in the skeletal remains of a lost tribe of nomads who herded cattle across the steppes of western Asia 5,000 years ago. It turns out that the nomads carried genetic mutations that most likely protected them from pathogens carried by their animals, but that also made their immune systems more sensitive. These genes, the study suggests, made the nomads’ descendants prone to a runaway immune response.

Continue reading “Ancient Skeletons Give Clues to Modern Medical Mysteries” →

Every spring, trillions of flowers mate with the help of bees and other animals. They lure the pollinators to their flowers with flashy colors and nectar. As the animals travel from flower to flower, they take pollen with them, which can fertilize the seeds of other plants.

A new study suggests that humans are quickly altering this annual rite of spring. As toxic pesticides and vanishing habitats have driven down the populations of bees and other pollinators, some flowers have evolved to fertilize their own seeds more often, rather than those of other plants.

Continue reading “Flowers Are Evolving to Have Less Sex” →

In 2015, while working as an undergraduate researcher at the North Carolina Zoo, Laura Lewis became friends with a male chimpanzee named Kendall. Whenever she visited the chimps, Kendall would gently take her hands and inspect her fingernails.

Then she disappeared for the summer to study baboons in Africa. When she returned to North Carolina, she wondered if Kendall would still remember her face. Sure enough, as soon as she stepped into his enclosure, Kendall raced up and gestured to look at her hands.

Continue reading “Chimps Can Still Remember Faces After a Quarter Century” →

Neanderthals were morning people, a new study suggests. And some humans today who like getting up early might credit genes they inherited from their Neanderthal ancestors.

The new study compared DNA in living humans with genetic material retrieved from Neanderthal fossils. It turns out that Neanderthals carried some of the same clock-related genetic variants as do people who report being early risers.

Continue reading “Morning Person? You Might Have Neanderthal Genes to Thank.” →

Why do we grow old and die?

In the 19th century, the German biologist August Weismann argued that the machinery of life inevitably wore out with time. Death had evolved “for the need of the species,” he declared. It cleared away weak, old individuals so they wouldn’t compete with young ones.

That explanation never made sense to George Williams, an American evolutionary biologist. Natural selection acts only on the genes that are passed down from one generation to the next. What happens at the end of an animal’s life can have no effect on the course of evolution.

Continue reading “Genes That Boost Fertility Also Shorten Our Life, Study Suggests” →