All posts tagged: human ancestry

Scientists are rethinking the origins of living apes

Scientists are rethinking the origins of living apes

Published by Jenni Sidey

A jaw bone discovered in Egypt is changing the way scientists think about the origins of the ape family tree. The specimen, which is thought to be about 17 or 18 million years old, was found in the Wadi Moghra region of northern Egypt. According to the researchers that worked on it, it could help fill a long-standing gap in the understanding of the evolution of modern-day apes. This discovery is significant because, for many years, the fossil record from North Africa during the Early Miocene contained only fossils belonging to monkeys, and no apes. Therefore, the focus of many researchers has been East Africa to understand where modern apes might have evolved. Although this new fossil provides only one additional specimen to the existing fossil record, it does reinforce the existence of apes further north than previously thought. Sallam Lab team from Mansoura University Vertebrate Paleontology Center. (CREDIT: Professor Hesham Sallam) “We have spent five years looking for this type of fossil,” said Hesham Sallam, a paleontologist with Mansoura University and the senior author …

Neanderthal males preferred human females, genetic study finds

Neanderthal males preferred human females, genetic study finds

Published by Jenni Sidey

Thin stretches of the human X chromosome look oddly empty when you scan for Neanderthal DNA. Geneticists even have a name for the gaps: “Neanderthal deserts.” They sit there like blank tape in an otherwise crowded recording. For years, the standard story went like this: Neanderthal DNA landed in our ancestors’ genomes. However, some of it was harmful, especially on the X chromosome. Natural selection, the thinking said, gradually stripped those “toxic” variants away. A new analysis from Sarah Tishkoff’s lab at the University of Pennsylvania argues that the emptiness may say more about who paired with whom than which genes were dangerous. In Science, the team reports a mirror-image pattern inside Neanderthal genomes. Neanderthals carried unusually high levels of modern human DNA on their X chromosomes compared with the rest of their genome. That reversal, they say, makes simple “toxicity” a much harder explanation to defend. The deserts and the old assumption “Along our X chromosomes, we have these missing swaths of Neanderthal DNA we call ‘Neanderthal deserts,’” says Alexander Platt, a senior research …