Humans

In his new book Novacene, James Lovelock says the creation of AlphaGo was the start of a new kingdom of life that will create and think for itself. He’s optimistic that this new kingdom of life will want to keep us around like we keep plants in gardens. In our interview at his house near Chesil Beach we discuss the future of Gaia, our new AI overlords and why Elon Musk’s Mars mission is crazy. More

Recent discoveries of fossils of ancient human relatives in southern Africa are disrupting our long-held ideas of the origins of humankind. Two of these discoveries, Australopithecus sediba and Homo naledi, represent significant contributions to this shakeup of our family tree. And there’s much more to come, as Berger explains in this interview with New Scientist […] More

Richard Dawkins is one of the world’s most famous scientists, a best-selling author – and a hugely controversial figure. His works on evolutionary biology inspired millions, but his bestselling book The God Delusion started a new phase of his career as an outspoken critic of all things religious. We met him at his home in Oxford to find out more. More

By Michael Marshall

The distribution of slavery in southern US states in 1860
Niday Picture Library / Alamy

A study of the DNA of people in the Americas with African heritage has revealed overlooked details about the transatlantic slave trade.
“This gives some clarity and some sense of individual history,” says historian Linda Heywood of Boston University in Massachusetts, who wasn’t involved in the research. DNA evidence means African Americans can pinpoint where their ancestors were abducted from and reclaim aspects of their heritage that were hidden by the slave trade, she says. “It broadens the way in which identity and personal history can be thought about.”
An estimated 12.5 million people were taken from Africa to the Americas between the 1500s and 1800s, according to historical texts like shipping documents and records of people being sold.

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To fill out the picture, Steven Micheletti of consumer genetics firm 23andMe in Sunnyvale, California, and his colleagues looked at DNA from 50,281 people, including 27,422 people from across the Americas with a minimum of 5 per cent African ancestry, 20,942 Europeans and 1917 Africans. This allowed them to identify stretches of DNA that are unique to people from particular regions of Africa.
The data came from 23andMe customers, along with public genome databases. Studies like this are becoming possible because African people, who were previously under-represented in genome databases, are now being asked to take part in research, says Joanna Mountain, also of 23andMe. Nevertheless, gaps remain. “I’m hoping we get some data from Mozambique sometime soon. It was involved in the slave trade, but we didn’t have enough data to include it in this study,” she says.

In line with historical records of where slaves were taken from, the African DNA in people in the Americas was most similar to that of people living in west African countries like Senegal, the Democratic Republic of the Congo and Angola.
However, most people in the Americas with African ancestry won’t have DNA from a single region of Africa. “Our results suggest the average African American would have connections to multiple regions,” says Micheletti. That is partly because slave traders disregarded ethnic identities, mixing people from different groups, and partly because African Americans moved around within the US. For instance, during the Great Migration of the 20th century African Americans moved from the segregated southern states of the US to northern states.
Because so many people were abducted as slaves, much of the genetic diversity in Africa was carried to the Americas, says Eduardo Tarazona-Santos at the Federal University of Minas Gerais in Belo Horizonte, Brazil. “But within the Americas, this diversity was more homogenised between populations.”

The analysis points to overlooked details of the slave trade. For instance, the team found less DNA from Senegal, Gambia and regions in other neighbouring countries than would be expected given the huge numbers of people taken from there. This may be because those slaves were often taken to rice plantations in the US, where the death rate was high due to malaria, says the team.

Meanwhile, many people in Central and South America and on many Caribbean islands today carry little African DNA – despite the fact that 70 per cent of slaves who survived the trip to the Americas were sent there.
This may reflect a form of racism once practised in Brazil, says Mountain, in which women of African descent were raped or forced to marry Europeans to promote “racial whitening”. In contrast, in the US, African Americans were often segregated from white people by law, and racial intermarriage was illegal or taboo.
The genetic data also confirms that female slaves have passed on much more of their DNA than male slaves – even though historical records show the majority of people taken from Africa were male. This is probably because female slaves were subjected to rape and sexual exploitation.
Journal reference: American Journal of Human Genetics, DOI: 10.1016/j.ajhg.2020.06.012
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Award-winning writer and campaigner Caroline Criado-Perez, speaks with New Scientist medical reporter Clare Wilson about how systematic gender biases are impacting women and men differently as the world copes with the coronavirus. For example, personal protective equipment is not only in short supply, its design – often based upon male body norms – is putting women at higher risk. Meanwhile, covid-19 affects men and women differently with men dying at a slightly higher rate, but many countries are not collecting sex-disaggregated data, making it difficult to understand the differences and mitigate some of the worst effects, she says. More

By Clare Wilson
A red fox raiding a bin on a residential street in London
Graham Racher / Alamy

We shouldn’t be surprised by how well foxes can survive by scavenging from our food leftovers – it is a behaviour that is tens of thousands of years old.
The ancestors of today’s foxes began living on humans’ food remains about 42,000 years ago, according to an analysis of animal bones found in Germany. “It’s the same as how they behave today in towns,” says Chris Baumann at the University of Tübingen in Germany.
Today, red foxes (Vulpes vulpes) and Arctic foxes (Vulpes lagopus) prey on small rodents in the wild as well as scavenging from the carcasses of animals, often those killed by large predators like bears and wolves. But the closer they live to towns and villages, the more their diet is made up of people’s food leftovers. “They’re very flexible,” says Baumann.

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He and his team analysed animal bones, including those of foxes, bears and wolves, found at sites in south-west Germany. The sites had been dated to three time periods: older than 42,000 years ago, when Neanderthals were the only humans living in the region, and two later periods when modern humans had moved in, lasting until 30,000 years ago.

By measuring the different isotopes of carbon and nitrogen in the bones, the team could work out what the animals had been eating. In the oldest period studied, foxes had eaten a mixture of animals, and these were likely to have been killed by bears, wolves and lions.
But after around 42,000 years ago, some of the foxes had switched to eating mainly reindeer. None of the other carnivores were mostly eating reindeer, so the foxes couldn’t have been scavenging from the kills of wolves, for instance.
While humans at the time ate a range of animals, including mammoths, “in cave sites, we find a lot of reindeer bones, because they are easy to transport as whole bodies to the caves”, says Baumann. “And if humans butchered them there, it would have produced food waste.”
Looking at the diet of foxes in other areas may become a new source of information about how ancient humans lived, says Baumann.

Journal reference: PLoS One, DOI: 10.1371/journal.pone.0235692
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