My Neanderthal sex secret: modern European's great-great grandparent link

The first modern humans to arrive in Europe did not wait long to have sex with Neanderthals, according to experts in ancient DNA.

Tests on the remains of a man who lived in Europe about 40,000 years ago found he had two to four times more Neanderthal DNA than any other modern human tested. He inherited the DNA when an ancestor had sex with a Neanderthal about 200 years earlier, or four to six generations back in his family tree.

Though present day humans have at most only a few percent Neanderthal DNA each, when added together, the global population carries about a fifth of the Neanderthal genome.

Genetic tests show that most Neanderthal DNA was rapidly lost from the modern human genome. One theory is that mixed children grew up to be less fertile, or were less likely to reach fertile age, meaning their DNA vanished quickly from the gene pool.

In the latest study, scientists used a dentist’s drill to remove a small amount of bone for genetic tests. The results, reported in Nature, are remarkable. The man had 6-9% Neanderthal DNA, far more than people alive today. But the amount was not the only surprise. The Neanderthal DNA was present in large chunks, meaning he had a Neanderthal ancestor in his recent past. Half of one entire chromosome was pure Neanderthal.

A great discovery that will help to understand better the human´s genome because it was unknown until today that our genome contains Neanderthal genes, even if it is that little.

Read more at: http://www.theguardian.com/science/2015/jun/22/my-neanderthal-sex-secret-modern-europeans-great-great-grandparent-link

Studies Suggest Homo naledi Walked Upright and Climbed Trees

Homo naledi – an extinct species of hominin whose fossil skeletons were discovered in a South African cave and introduced to the world last month – may have been uniquely adapted for both tree climbing and walking as dominant forms of movement, while also being capable of precise manual manipulation, according to two new studies published in the journal Nature Communications.

One of the studies, titled The foot of Homo naledi, suggests that although its feet were the most human-like part of its body, Homo naledi didn’t use them to walk in the same way we do. They show the Homo naledi foot shares many features with a modern human foot, indicating it is well-adapted for standing and walking on two feet.

The Homo naledi hand and foot were uniquely adapted for both tree climbing and walking upright. The hand of Homo naledi reveals a unique combination of anatomy that has not been found in any other fossil human before. The wrist bones and thumb show anatomical features that are shared with Neanderthals and humans and suggest powerful grasping and the ability to use stone tools.

This mix of human-like features in combination with more primitive features demonstrates that the Homo naledi hand was both specialized for complex tool-use activities, but still used for climbing locomotion.

From our point of view, it is an amazing discovery in terms of anthropology because it totally changes the perception of human evolution and Homo naledi's bipedalism and capability to climb trees. This information did not fit in human evolution steps until today.

Regardless of age, this species is going to cause a paradigm shift in the way we think about human evolution, not only in the behavioral implications, but in morphological and anatomical terms

Read more at: http://www.sci-news.com/othersciences/anthropology/science-homo-naledi-foot-hand-03313.html

Teeth from China Reveal an Early Human Trek out of Africa

       "Stunning" find shows that Homo sapiens reached Asia around 100,000 years ago.

Teeth from a cave in south China show that Homo sapiens reached China around 100,000 years ago—a time at which most researchers had assumed that our species had not trekked far beyond Africa.

Recent excavations of a cave system there extending over 3 square kilometres discovered 47 human teeth, as well as dozens of other animal species. The researchers found no stone tools; it is likely that humans never lived in the cave and their remains were instead hauled in by predators.

The teeth are unquestionably those of H. sapiens. The team report their results in Nature today. Determining the age of the teeth proved tricky. They contained no radioactive carbon (which has almost vanished after 50,000 years). So the team dated various calcite deposits in the cave and used the assortment of animal remains to deduce that the human teeth were probably between 80,000 and 120,000 years old.

Early trekkers

Those ages buck the conventional wisdom that H. sapiens from Africa began colonizing the world only around 50,000–60,000 years ago. But many researchers had argued that those remains were only evidence of unsuccessful efforts at wider migration.

Without DNA from the teeth, it is impossible to determine the relationship between the Daoxian people and other humans, including present-day Asians.

Other genetic evidence sugests that present-day East Asians descend from humans who interbred with Neanderthals in western Asia some 55,000–60,000 years ago. It is also not clear why modern humans would have reached East Asia so long before they reached Europe, where the earliest remains are about 45,000 years old. The frigid climate of Ice Age Europe may have erected another barrier to people adapted to Africa.

Although there´s a lot more work that needs to be done, this great discovery will surely change the common idea of the incapability of the early humans to adapt to new environments.

Read more at:  http://www.nature.com/news/teeth-from-china-reveal-early-human-trek-out-of-africa-1.18566

2-million-year-old fossils reveal hearing abilities of early humans

Research into human fossils dating back to approximately two million years ago reveals that the hearing pattern resembles chimpanzees, but with some slight differences in the direction of humans.

The study relied on the use of CT scans and virtual computer reconstructions to study the internal anatomy of the ear. The results suggest that the early hominin species Australopithecus africanus and Paranthropus robustus, both of which lived around 2 million years ago, had hearing abilities similar to a chimpanzee, but with some slight differences in the direction of humans. 

Humans are distinct from most other primates, including chimpanzees, in having better hearing across a wider range of frequencies. Within this same frequency range, which encompasses many of the sounds emitted during spoken language, chimpanzees and most other primates lose sensitivity compared to humans.

In the South African fossils, the region of maximum hearing sensitivity was shifted towards slightly higher frequencies compared with chimpanzees, and the early hominins showed better hearing than either chimpanzees or humans. It turns out that this auditory pattern may have been particularly favorable for living on the savanna. In more open environments, sound waves don't travel as far as in the rainforest canopy, so short range communication is favored on the savanna.

The emergence of language is one of the most hotly debated questions in paleoanthropology. There is a general consensus among anthropologists that the small brain size and ape-like cranial anatomy and vocal tract in these early hominins indicates they likely did not have the capacity for language.

How do these results compare with the discovery of a new hominin species, Homo naledi, announced just two weeks ago from a different site in South Africa?

It is obvious that this research is going to be a big step in anthropology and also in other sciences as medicine, because it may help in understanding the different patterns of audition and how and why have they evolved in this direction and not in another one.

Read more at: http://www.sciencedaily.com/releases/2015/09/150925142702.htm