11,000-year-old child’s skeleton tells tale of Native American origins

Enlarge / Excavations at the Upward Sun River site. (credit: Ben Potter) Where did Native Americans come from? Over the years, lots of ideas have been considered, but genetic data eventually came down decisively in favor of one of them. Native Americans are most closely related to East Asians and must have come across a land bridge that was present between Siberia and Alaska during the last glacial period. But that big-picture answer has raised all sorts of additional questions about the details. There has been a long-running argument over their mode of travel, which only recently seems to have been decided in favor of boats . There are still arguments over how many waves of migration took place. And a weak genetic affinity for Eurasian populations, strengthened by an ancient Siberian genome , raises questions about how that DNA ended up in Native American genomes. Now, a large team of researchers is saying they have data that clarifies a lot of these questions. It comes in the form of a genome obtained from a child’s skeleton found in Alaska. The skeleton has been dated to 11,500 years ago, and the genome now suggests it represents a member of a now-lost population that occupied the Beringian land bridge at the peak of the last glacial period—and gave rise to Native Americans. Read 10 remaining paragraphs | Comments

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11,000-year-old child’s skeleton tells tale of Native American origins

The complete history of the IBM PC, part two: The DOS empire strikes

Nota bene: This is the concluding part of the surprisingly interesting history of the IBM PC. You should probably read part one of the story if you haven’t already. In November 1979, Microsoft’s frequent partner Seattle Computer Products released a standalone Intel 8086 motherboard for hardcore hobbyists and computer manufacturers looking to experiment with this new and very powerful CPU. The 8086 was closely related to the 8088 that IBM chose for the PC; the latter was a cost-reduced version of the former, an 8-bit/16-bit hybrid chip rather than a pure 16-bit like the 8086. Read 44 remaining paragraphs | Comments

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The complete history of the IBM PC, part two: The DOS empire strikes

Dinosaur eggs reveal one possible reason why they went extinct

The eggs of some dinosaurs took much, much longer to hatch than the eggs of their avian relatives and descendants — and it could have contributed to their demise. A team of researchers from various institutions examined the embryonic tooth from a soccer-ball-sized egg. It was laid by a 30-foot-long duck-billed non-avian dinosaur called Hypacrosaurus that’s closely related to reptiles like crocodiles. By calculating the daily growth markers in the teeth, they discovered that the animal’s eggs take around six months to hatch. It’s also likely that the bigger the egg, the longer the incubation time. In comparison, ostrich chicks burst out of their shells after only 42 days, and smaller birds have even shorter incubation periods. A longer incubation time means non-avian dinosaurs were definitely at a disadvantage when an asteroid or a comet slammed into our planet 65 million years ago. Since it took much longer for them to reproduce and to replace the population that perished in the impact, their incubation period could be one of the factors that led to their extinction. Meanwhile, the birds that already existed in that era that didn’t need the same amount of time to hatch thrived and led to the birds we know today. That said, their long incubation period is only one of the factors why they died out. Lead researcher Gregory M. Erickson of Florida State University said: “These animals were profligate wasters of energy. They were big and warmblooded and even the smallest dinosaurs took over a year to mature. The dinosaurs found themselves holding some bad cards. They had a dead man’s hand.” Source: The New York Times

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Dinosaur eggs reveal one possible reason why they went extinct