Archive for the ‘DNA & HISTORY’ Category

Neanderthal tooth plaque reveals paleo-diet & the use of aspirin

ANCIENT DNA from dental plaque is revealing intriguing new information about Neanderthals including specific menu items in their diet like woolly rhinoceros and wild mushrooms as well as their use of plant-based medicine to cope with pain and illness.

Australian-led researchers have genetically analysed plaque from 48,000-year-old Neanderthal remains from Spain and 36,000-year-old remains from Belgium. The plaque, material that forms on and between teeth, contained food particles as well as microbes from the mouth as well as respiratory and gastrointestinal tracts.

Work in the Tunnel of Bones cave, where 12 Neanderthal specimens dating around 49,000 years ago have been recovered. Picture: Antonio Rosas/Paleoanthropology Group / AP

At Belgium’s Spy Cave site, which at the time was a hilly grassy environment home to big game, the Neanderthal diet was meat-based with woolly rhinoceros and wild sheep, along with wild mushrooms.

Some 12,000 years earlier, at Spain’s El Sidron Cave site, which was a densely forested environment likely lacking large animals, the diet was wild mushrooms, pine nuts, moss and tree bark, with no sign of meat.

The two populations apparently lived different lifestyles shaped by their environments, the researchers said.

An El Sidron upper jaw: a dental calculus deposit is visible on the rear molar, right, of this Neanderthal. Picture: Paleoanthropology Group MNCN-CSIC / AP

The researchers found that an adolescent male from the Spanish site had a painful abscess and an intestinal parasite that causes severe diarrhoea. The plaque DNA showed he had consumed poplar bark, containing the painkilling active ingredient of aspirin, and a natural antibiotic mould.

“This study really gives us a glimpse of what was in a Neanderthal’s medicine cabinet,” said paleomicrobiologist Laura Weyrich of Australia’s University of Adelaide, lead author of the study published in the journal Nature.

Analysis of Neanderthal tooth plaque hints at what they may have eaten – and kisses

The findings added to the growing body of knowledge about Neanderthals, the closest extinct relative of our species, Homo Sapiens, and further debunked the outdated notion of them as humankind’s dimwitted cousins.

“I definitely believe our research suggests Neanderthals were highly capable, intelligent, likely friendly beings. We really need to rewrite the history books about their ‘caveman-like’ behaviours. They were very human-like behaviours,” Weyrich said.

The robust, large-browed Neanderthals prospered across Europe and Asia from about 350,000 years ago until going extinct roughly 35,000 years ago after our species, which first appeared in Africa 200,000 years ago, established itself in regions where Neanderthals lived.

Scientists say Neanderthals were intelligent, with complex hunting methods, probable use of spoken language and symbolic objects, and sophisticated fire usage.

The researchers also reconstructed the genome of a 48,000-year-old oral bacterium from one of the Neanderthals.

“This is the oldest microbial genome to date, by about 43,000 years,” Weyrich said.

Henry Sapiecha

The bite evolution: Your teeth will tell where you came from

Research led by Monash University evolutionary biologist Alistair Evans has shown teeth track evolution-image www.perfectwhiteteeth.net

Research led by Monash University evolutionary biologist Alistair Evans has shown teeth track evolution. Photo: Simon Schluter

Science reveals the secrets of super-sized mammals

Modern diet helping bacteria to wreck our teeth

They’re good for biting, chewing and filling out a cheesy smile for the camera. But teeth have also been shown to be a surprisingly nifty way to track human evolution.

New research has shown that the evolution of teeth, long thought to be a random process, follows a pattern.

A team of international researchers led by Monash University evolutionary biologist Alistair Evans established the pattern applies to up to 90 per cent of human, mammal and hominins.
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The main rule is that the biggest teeth for australopiths (the first branch of the hominin tree from which humans evolved) are their back molars, or wisdom teeth. Meanwhile the biggest teeth in humans is the front molar.

“It was always hard to see the forest for the trees because every fossil had to be looked at independently. But here we can see a general pattern and we can be sure that it’s definitely the case,” Dr Evans said.

The newly-defined developmental pattern, outlined in the journal Nature on Thursday, is known as “the inhibitory cascade”.

It sheds lights on how humans and other mammals develop teeth, a process which begins in the embryo.

Understanding how teeth form has uses in fields from academia to cosmetic and medical treatments.

“If we want to do any bioengineering, say grow-your-own teeth, we need to understand these processes,” Dr Evans said. “It’s fundamental research.”

The findings will also enable palaeontologists working with incomplete fossilised jaws to literally “fill in the gaps” and make an informed assessment of the size of the missing teeth.

Dr Evans said when looking at three teeth in a row, the middle tooth would be the average size of the teeth sitting either side.

“This gives us a starting point, as we can compare any new fossil with our expectations … and if we do find some exceptions or changes then we can say ‘well, something really interesting must be happening here’,” he said.

But more importantly, the realisation gives a sense of order to a process previously believed to be random.

“When people had looked at human evolution before they thought ‘everything’s changing all over the place and it’s all very confusing’,” Dr Evans said. “But what we have now is a general framework or a default pattern of development to say that pretty much all hominins and probably all mammals develop in this same way.”

The size and proportion of teeth can reveal not only when meat started to be eaten but also when cooking and the use of tools began. Each of these changes affect tooth size, because suddenly teeth could be smaller.

The 11-member research team began looking at mouse tooth development and established the “inhibitory cascade” rule before confirming the pattern in humans.

To do that they studied tooth measurements from every hominin fossil found to establish that the pattern existed there, which it did. The researchers then tested their theory out on great ape and human data to see if the pattern was evident.

“It was very obvious, immediately,” Dr Evans said. “But nobody had noticed it before.”

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Henry Sapiecha