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Humans to blame for Creation of World’s Largest hot Sahara Desert: Study

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Hot Sahara Desert, Credits: Wikimedia
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Seoul, March 15, 2017: Challenging a commonly held theory that changes in the Earth’s orbit triggered Sahara desertification, a new study suggests that humans may have played an active role in the transition of a lush green landscape into the world’s largest hot desert thousands of years ago.

The desertification of the Sahara has long been a target for scientists trying to understand climate and ecological tipping points.

Most studies done to date point to changes in the Earth’s orbit or natural changes in vegetation as the major driving forces.

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In a new paper published in the journal Frontiers in Earth Science, David Wright from Seoul National University in South Korea challenges the conclusions of these studies.

“In East Asia there are long established theories of how Neolithic populations changed the landscape so profoundly that monsoons stopped penetrating so far inland,” said Wright.

Evidence of human-driven ecological and climatic change has been documented in Europe, North America and New Zealand, said Wright who believed that similar scenarios could also apply to the Sahara.

To test his hypothesis, Wright reviewed archaeological evidence documenting the first appearances of pastoralism across the Saharan region, and compared this with records showing the spread of scrub vegetation, an indicator of an ecological shift towards desert-like conditions.

The findings confirmed his thoughts.

Beginning approximately 8,000 years ago in the regions surrounding the Nile River, pastoral communities began to appear and spread westward, increasing at the same time the spread of scrub vegetation, the study said.

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Growing agricultural addiction had a severe effect on the region’s ecology. As more vegetation was removed by the introduction of livestock, it increased the albedo (the amount of sunlight that reflects off the earth’s surface) of the land, which in turn influenced atmospheric conditions sufficiently to reduce monsoon rainfall.

The weakening monsoons caused further desertification and vegetation loss, promoting a feedback loop which eventually spread over the entirety of the modern Sahara, the study said. (IANS)

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Scientists Unveil a Tool That Can Predict Eye, Hair and Skin Color From DNA Sample

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Genes are a part of DNA/RNA.
Genes- A segment of DNA. Pixabay

Researchers have developed a novel web tool that can accurately predict eye, hair and skin color from even a small DNA sample, an advance that can be used when standard forensic profiling is not helpful.

The “HIrisPlex-S DNA test” system is capable of generating all three pigment traits from human biological material together using a freely available web tool.

The tool is designed to be used when standard forensic DNA profiling is not helpful because no reference DNA exists against which to compare the evidence sample.

The study, conducted on mice, found that genetic variations in the genes that codes for protein POU6F2 may affect the structure of the eye and increase a person's risk of glaucoma. Pixabay
Eye, representational image. pixabay

“We have previously provided law enforcement and anthropologists with DNA tools for eye colour and for combined eye and hair colour, but skin colour has been more difficult,” said Susan Walsh, forensic geneticist at the Indiana University-Purdue University Indianapolis in the US.

Users, such as law enforcement officials or anthropologists, can enter relevant data using a laboratory DNA analysis tool, and the web tool will predict the pigment profile of the DNA donor.

“Importantly, we are directly predicting actual skin colour divided into five subtypes — very pale, pale, intermediate, dark and dark to black — using DNA markers from the genes that determine an individual’s skin coloration.

"This study provided evidence that fasting induces a metabolic switch in the intestinal stem cells, from utilizing carbohydrates to burning fat," said David Sabatini, an MIT professor of biology and the paper's another senior author.
DNA, Pixabay

“If anyone asks an eyewitness what they saw, the majority of time they mention hair colour and skin colour. What we are doing is using genetics to take an objective look at what they saw,” Walsh said.

Also Read: This DNA Test Can Screen Your Baby For 193 Genetic Diseases

The results are published in the journal, Forensic Science International: Genetics.

The innovative high-probability and high-accuracy complete pigmentation profile web tool is available online without charge, the researchers said. (IANS)