In 1985, the chemist Steven A. Benner sat down with some colleagues and a notebook and sketched out a way to expand the alphabet of DNA. He has been trying to make those sketches real ever since.

On Thursday, Dr. Benner and a team of scientists reported success: in a paper, published in Science, they said they have in effect doubled the genetic alphabet.

Natural DNA is spelled out with four different letters known as bases — A, C, G and T. Dr. Benner and his colleagues have built DNA with eight bases — four natural, and four unnatural. They named their new system Hachimoji DNA (hachi is Japanese for eight, moji for letter).

Continue reading “DNA Gets a New — and Bigger — Genetic Alphabet” →

Over the past decade, the Denisova Cave in Siberia has yielded some of the most fascinating fossils ever found. To the naked eye, they are not much to look at — a few teeth, bits of bone.

But the fossils contain DNA dating back tens of thousands of years. That genetic material shows that Denisovans were a distinct branch of human evolution, a lost lineage.

At some point in the distant past, the Denisovans disappeared — but not before interbreeding with modern humans. Today, people in places like East Asia and New Guinea still carry fragments of Denisovan DNA.

Continue reading “High Ceilings and a Lovely View: Denisova Cave Was Home to a Lost Branch of Humanity” →

In 2014 John Cryan, a professor at University College Cork in Ireland, attended a meeting in California about Alzheimer’s disease. He wasn’t an expert on dementia. Instead, he studied the microbiome, the trillions of microbes inside the healthy human body.

Dr. Cryan and other scientists were beginning to find hints that these microbes could influence the brain and behavior. Perhaps, he told the scientific gathering, the microbiome has a role in the development of Alzheimer’s disease.

Continue reading “Germs in Your Gut Are Talking to Your Brain. Scientists Want to Know What They’re Saying.” →

In the 1800s, thousands of Aboriginal Australians were the victims of a terrible trade in the name of science. Anatomists opened their graves and stole their skeletons. After massacres of Aboriginal Australians, police officers sold body parts to museums.

Today, many of these bones lie far from home.

“Our old people’s remains have been stolen from this country, and they’re global, whether they be in London, Germany, Sweden, Switzerland — even in America,” said Gudju Gudju Fourmile, an elder of the Yidniji and Gimuy Walubara people in northern Australia.

Continue reading “‘Spirits Won’t Rest’: DNA Links Ancient Bones to Living Aboriginal Australians” →