Isolated Greenland polar bear population adapts to climate change
An isolated population of polar bears in Greenland has made a clever adaptation to the decline in the sea ice they depend upon as a platform for hunting seals, offering a ray of hope for this species in at least some locales in the warming Arctic. This population of several hundred bears, inhabiting part of Greenland's southeast coast on the Denmark Strait, has survived with only abbreviated access to ice formed from frozen seawater by hunting instead of chunks of freshwater ice breaking off from the huge Greenland Ice Sheet, researchers said on Thursday.
Ancient DNA solves the mystery over the origin of the medieval Black Death
Ancient DNA from bubonic plague victims buried in cemeteries on the old Silk Road trade route in Central Asia has helped solve an enduring mystery, pinpointing an area in northern Kyrgyzstan as the launching point for the Black Death that killed tens of millions of people in the mid-14th century.
Researchers said on Wednesday they retrieved ancient DNA traces of the Yersinia pestis plague bacterium from the teeth of three women buried in a medieval Nestorian Christian community in the Chu Valley near Lake Issyk Kul in the foothills of the Tian Shan mountains who perished in 1338-1339. The earliest deaths documented elsewhere in the pandemic were in 1346.
Ancient DNA from bubonic plague victims buried in cemeteries on the old Silk Road trade route in Central Asia has helped solve an enduring mystery, pinpointing an area in northern Kyrgyzstan as the launching point for the Black Death that killed tens of millions of people in the mid-14th century.
Researchers said they retrieved ancient DNA traces of the Yersinia pestis plague bacterium from the teeth of three women buried in a medieval Nestorian Christian community in the Chu Valley near Lake Issyk Kul in the foothills of the Tian Shan mountains who perished in 1338-1339. The earliest deaths documented elsewhere in the pandemic were in 1346.
Reconstructing the pathogen’s genome showed that this strain not only gave rise to the one that caused the Black Death that mauled Europe, Asia, the Middle East and North Africa but also to most plague strains existing today.
“Our finding that the Black Death originated in Central Asia in the 1330s puts centuries-old debates to rest,” said historian Philip Slavin of the University of Stirling in Scotland, co-author of the study published in the journal Nature.
The Silk Road was an overland route for caravans carrying a panoply of goods back and forth from China through the sumptuous cities of Central Asia to points including the Byzantine capital Constantinople and Persia. It also may have served as a conduit of death if the pathogen hitched a ride on the caravans.
“There have been a number of different hypotheses suggesting that the pandemic may have originated in East Asia, specifically China, in Central Asia, in India, or even close to where the first outbreaks were documented in 1346 in the Black Sea and Caspian Sea regions,” said archaeogeneticist and study lead author Maria Spyrou of the University of Tübingen in Germany.
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