Tag Archives: Jenn Gidman

Europeans’ white skin developed later than thought

Europeans' white skin developed later than thought

Sweden’s Crown Princess Victoria and Prince Daniel in 2011. Traits of white skin emerged more recently than thought in Europe. (AP Photo/Lehtikuva/Vesa Moilanen)

Science notes that Europe is often thought of as the “ancestral home of white people.” But a new DNA study suggests that pale skin and other traits we associate with the continent may have emerged only within the last 8,000 years—a “relatively recent” occurrence.

The study—published last month on the bioRxiv.com server and presented last week at the American Association of Physical Anthropologists’ annual meeting—compared genome DNA across three populations of farmers and hunter-gatherers who crossed over into Europe in discrete migrations within the past eight millennia, Science notes.

What scientists found: a handful of genes tied to diet and skin pigmentation that withstood natural selection and thrived in the northern regions. The data indicates hunter-gatherers who settled in Spain, Hungary, and Luxembourg about 8,500 years ago lacked two specific genes—SLC24A5 and SLC45A2—and had darker skin, Science notes.

But hunter-gatherers hunkered down further north in Sweden had both those light-skin genes and also a third gene that leads to blue eyes (and possibly fair skin and blond hair).

When the third demographic, the Near East farmers, arrived, they also carried the SLC24A5 and SLC45A2 genes, so paler skin started emerging throughout the continent as the populations interbred.

Although researchers don’t offer a definitive answer as to why natural selection picked those genes to thrive in the north, one paleoanthropologist speculated at the meeting that the lack of sun in the northern parts of Europe required people to adapt by developing lighter skin to better absorb more vitamin D, as well as the LCT gene that allowed them to digest the sugars their ancestors couldn’t in milk, also filled with vitamin D.

(This one infant could tell us where the first Americans came from.)

This article originally appeared on Newser: Europeans’ White Skin Came Later Than Thought

Advertisements

1 Comment

Filed under Humor and Observations

Does ‘Blue Hole’ hold secret to Mayan collapse?

Does 'Blue Hole' hold secret to Mayan collapse?

This undated image provided by the Belize Tourist Board shows an aerial view of the Great Blue Hole, a popular diving site that’s part of Belize���s barrier reef. (AP Photo/Belize Tourist Board)

Everything from overhunting and a peasant uprising to deforestation and an alien invasion has been proposed to explain why the Mayan civilization collapsed,Smithsonian notes. But one theory has been gaining ground in recent years: extreme drought.

Now more evidence has surfaced to support the drought postulation—and the proof may just lie in Belize’s most famous underwater cave. Rice University professor Andre Droxler’s team analyzed sediment found in the “Great Blue Hole,” a 410-foot-deep sinkhole in the middle of Lighthouse Reef, LiveSciencereports.

Not only did the chemical composition of the silt indicate periods of sparse rainfall during the Mayan decline (likely between AD800 and AD1000): It also showed that a second huge drought probably occurred between AD1000 and AD1100—right around the time the Mayans’ relocation site of Chichen Itza is said to have fallen.

Over thousands of years, runoff from rivers and streams during periods of ample rainfall deposited layers of sediment in the Blue Hole’s lagoon, offering scientists a geological timeline to examine.

“It’s like a big bucket,” Droxler tells LiveScience. “It’s a sediment trap.” Excessive rain also erodes volcanic rock, which contains titanium. Droxler’s team found that the sediment’s mineral composition—specifically, the low ratio of titanium to aluminum—in the lagoon indicated periods of low rainfall during the times when the Mayas, for the most part, disappeared.

Scientists surmise that due to a climate glitch, monsoons may have skipped over the Yucatan Peninsula during these periods, leading to eventual catastrophe all around. “When you have major droughts, you start to get famines and unrest,” Droxler explains.

(A “lost” Mayan city with 15 pyramids was discovered in Mexico last year.)

This article originally appeared on Newser: ‘Blue Hole’ May Hold Secret to Mayan Collapse

Leave a comment

Filed under Humor and Observations

Boy, 11, finds 3,000-year-old sword in river

As he dunked them into the water, he felt something graze his hand, pulled it out, and brought it home to show his dad, reports Xinhua.

Now experts say “it” turns out to be a 3,000-year-old bronze sword, probably from either the Shang or Zhou dynasty—”the dawn of Chinese civilization,” as the BBC puts it.

The head of the Gaoyou Cultural Relics Bureau thinks the 10-inch sword likely belonged to a civil official, since “it has both decorative and practical functions, but is not in the shape of [a] sword for military officers.” Recent dredging of the river may have brought the sword out of the silt and closer to the surface, according to the bureau official, who adds that archaeologists are now planning a larger dig there.

The boy’s dad admits that locals wanted to buy the sword from him for “high prices,” but he “felt it would be illegal to sell the cultural relic.” The bureau sent him and his inquisitive son a certificate and reward for finding the piece.

Leave a comment

Filed under Humor and Observations