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"Neanderthal Boy," Michael McCullough, Flickr // CC BY-NC-ND 2.0

Humans and Neanderthals Interbred 40,000 Years Earlier Than We Thought

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"Neanderthal Boy," Michael McCullough, Flickr // CC BY-NC-ND 2.0

We've known for a while that some Neanderthals and early modern humans mated; most of us still carry a small percentage of Neanderthal DNA (which may have some ill effects on us). But when exactly did that mating take place? An article, published in the journal Nature, suggests that interbreeding between humans and Neanderthals began 100,000 years ago. This extends the previously accepted timeline by 40,000 years, the BBC reports.

For the study, the scientists used the genome of a female Neanderthal who was discovered in a remote cave in the mountains of Siberia. While Neanderthal DNA found in modern humans supports the idea that the two groups met during migration out of Africa between 47,000 and 65,000 years ago, the presence of human DNA in the Neanderthal woman adds an earlier encounter to the narrative. That evidence may change what we knew about when migration out of Africa started and where early modern humans went.

"We conclude that in addition to later interbreeding events, the ancestors of Neanderthals from the Altai Mountains and early modern humans met and interbred, possibly in the Near East, many thousands of years earlier than previously thought," the scientists wrote.

Paleoanthropologist Chris Stringer of the Natural History Museum in London, who was not involved in the study, told the BBC that experts still aren't sure exactly where those interbreeding events took place. "We really don't know how widespread Neanderthals and early modern humans might have been in the regions between Arabia and China at this time," he said.

Stringer added that scientists are also unsure about the nature of the events or whether they were even consensual. One way to tell the difference would be to determine if human DNA was transferred solely from males to females or if there was a balance. Stringer says a lot more data is needed to determine that.

[h/t BBC]

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Land Cover CCI, ESA
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Afternoon Map
European Space Agency Releases First High-Res Land Cover Map of Africa
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Land Cover CCI, ESA

This isn’t just any image of Africa. It represents the first of its kind: a high-resolution map of the different types of land cover that are found on the continent, released by The European Space Agency, as Travel + Leisure reports.

Land cover maps depict the different physical materials that cover the Earth, whether that material is vegetation, wetlands, concrete, or sand. They can be used to track the growth of cities, assess flooding, keep tabs on environmental issues like deforestation or desertification, and more.

The newly released land cover map of Africa shows the continent at an extremely detailed resolution. Each pixel represents just 65.6 feet (20 meters) on the ground. It’s designed to help researchers model the extent of climate change across Africa, study biodiversity and natural resources, and see how land use is changing, among other applications.

Developed as part of the Climate Change Initiative (CCI) Land Cover project, the space agency gathered a full year’s worth of data from its Sentinel-2A satellite to create the map. In total, the image is made from 90 terabytes of data—180,000 images—taken between December 2015 and December 2016.

The map is so large and detailed that the space agency created its own online viewer for it. You can dive further into the image here.

And keep watch: A better map might be close at hand. In March, the ESA launched the Sentinal-2B satellite, which it says will make a global map at a 32.8 feet-per-pixel (10 meters) resolution possible.

[h/t Travel + Leisure]

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iStock
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Scientists May Have Found the Real Cause of Dyslexia—And a Way to Treat It
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iStock

Dyslexia is often described as trying to read letters as they jump around the page. Because of its connections to reading difficulties and trouble in school, the condition is often blamed on the brain. But according to a new study published in Proceedings of the Royal Society B, the so-called learning disability may actually start in the eyes.

As The Guardian reports, a team of French scientists say they've discovered a key physiological difference between the eyes of those with dyslexia and those without it. Our eyes have tiny light-receptor cells called rods and cones. The center of a region called the fovea is dominated by cones, which are also responsible for color perception.

Just as most of us have a dominant hand, most have a dominant eye too, which has more neural connections to the brain. The study of 60 people, divided evenly between those with dyslexia and those without, found that in the eyes of non-dyslexic people, the arrangement of the cones is asymmetrical: The dominant eye has a round, cone-free hole, while the other eye has an unevenly shaped hole. However, in people with dyslexia, both eyes have the same round hole. So when they're looking at something in front of them, such as a page in a book, their eyes perceive exact mirror images, which end up fighting for visual domination in the brain. This could explain why it's sometimes impossible for a dyslexic person to distinguish a "b" from a "d" or an "E" from a "3".

These results challenge previous research that connects dyslexia to cognitive abilities. In a study published earlier this year, people with the condition were found to have a harder time remembering musical notes, faces, and spoken words. In light of the new findings, it's unclear whether this is at the root of dyslexia or if growing up with vision-related reading difficulties affects brain plasticity.

If dyslexia does come down to some misarranged light-receptors in the eye, diagnosing the disorder could be as simple as giving an eye exam. The explanation could also make it easy to treat without invasive surgery. In the study, the authors describe using an LED lamp that blinks faster than the human eye can perceive to "cancel out" one of the mirror images perceived by dyslexic readers, leaving only one true image. The volunteers who read with it called it a "magic lamp." The researchers hope to further experiment with it to see see if it's a viable treatment option for the millions of people living with dyslexia.

[h/t The Guardian]

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