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First Denisovan fossil found outside of Siberia — our ancient “cousins” spread far and wide

When the first Denisovan fossil was found in 2010, it was hailed as a stunning discovery. Here was another species related to humans, clearly distinct from the Neanderthals and Homo sapiens. However, fossil evidence of this species had only been found in the Denisova Cave in Siberia, from which the Denisovans were named.

Now, a new fossil discovered in Tibet shows that the Denisovans weren’t nearly as localized as some thought. They spread far and wide, being capable of living at impressive altitudes.

Virtual reconstruction of the jawbone. Image credits: Jean-Jacques Hublin, MPI-EVA, Leipzig.

High Denisovans

Back in 1980, a Tibetan monk found a rather unusual fossil: a seemingly human jawbone. The monk passed it on to Lanzhou University, but the fragment was ignored until the 2010s when archaeologist Dongju Zhang and her colleagues began studying the bone. A recent study has now confirmed that the jawbone belonged to a Denisovan, a group of humanoids that lived alongside humans and Neanderthals, interbreeding with them several times across history.

Although genetic analysis has shown that the Denisovans were a unique group, remains from them have been sparse, and until now, limited only to the Denisova Cave. Of course, it’s not plausible that a humanoid group inhabited a single cave, so the hunt was on for other fossils. Jean-Jacques Hublin of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, wondered if they could find such remains in the Tibetan plateau, and turned to the jawbone from Lanzhou University.

Denisovans split from humans about 550,00–765,000 years ago, but we still carry some of their genetic legacies. Previous studies have suggested that Denisovans were well adapted to living in cold environments and at high altitudes, but the fact that they could survive in Tibet is remarkable.

The altitude of the new Denisovan’s home is 3,280 meters ( 10,700 feet) above sea level, an altitude at which you need special adaptations to be able to survive. This also changes the anthropological history of Tibet and the Himalayas, as previous research claimed that the area was first populated by humans around 40,000 years ago. This new finding pushes that date back by 100,000 years.

The fossil was found in this type of Tibetan landscape. Image credits: Dongju Zhang, Lanzhou University.

It’s not completely surprising, however — actually, this finding might help solve one pressing riddle about the genetic history of the Tibetan people: Tibetans and other populations in the region have a gene inherited from Denisovans that helps them live at high altitudes, but how they got this gene from the Denisovans in the first place is a mystery. The fact that Denisovans developed it in the first place was just as puzzling, considering that their only remains had been found in a low-lying area.

“Frankly speaking, until today, nobody ever imagined that archaic humans could be able to dwell in such an environment,” said Jean-Jacques Hublin, a co-author and paleoanthropologist at the Max Planck Institute for Evolutionary Anthropology. “It’s a big surprise because most people thought that challenging environments like the high altitudes were colonized only by modern humans like us less than 40,000 years ago.”

No DNA

Identifying what species the jawbone came from is no easy feat. The fragment is at least 160,000 years old, and DNA tends to disintegrate much quicker than that. So instead, researchers looked at a specific set of proteins, which is much more durable than DNA. Essentially, the strings of amino acids found in some protein can be a tell-tale sign of a particular species.

“Just like DNA, the amino acids in these proteins are ordered in a particular way,” said co-author Frido Welker, a researcher at the Max Planck Institute for Evolutionary Anthropology. “And we can actually sequence these proteins, so we can read the order of those amino acids.”

Of course, DNA analysis would still be much better. This type of protein analysis is still a nascent field, with a low sample size. But for the lack of a better approach, it offers much-needed information. Researchers also hope that these patterns could help determine other bones that they discovered. Researchers working in China have found several such fossils which are still unidentified.

“In China there are a number of specimens that are not Homo erectus, that are not modern humans, and that are good candidates for being Chinese Denisovans,” Hublin said. “But this has been impossible to prove today because in these fossils there is no ancient DNA preserved.”

“I predict that most of the Chinese hominin fossil record younger than 350,000 years and older than 50,000 is made of Denisovans,” he adds.

Identifying these remains could offer some valuable puzzle pieces as to who the Denisovans were, what they looked like, and how they passed on their genes. Also, if Hublin is right, this might help settle the debate over whether our ancestors evolved solely in Africa, or whether Asia played an important role too.

The study was published in the journal Nature.

Cordyceps sinensis on caterpillars from collection of Womens collective, Munsiyari. Credit: Wikimedia Commons.

A parasite worth three times its weight in gold is disappearing — and with it hundreds of thousands of jobs

Cordyceps sinensis on caterpillars from collection of Womens collective, Munsiyari. Credit: Wikimedia Commons.

Cordyceps sinensis on caterpillars from collection of Womens collective, Munsiyari. Credit: Wikimedia Commons.

During the summer days, thousands gather on the Tibetan plateau on the lookout for that year’s most prized commodity — buried orange sticks that look like withered carrots with a dark-brown rod at the top. The orange lump is, in fact, a dead caterpillar while the stick is a parasitic fungus that has devoured the unfortunate insect. If you’re not impressed yet, understand that the caterpillar fungus can sell for three times more than gold, kilogram for kilogram.

But a new study is confirming what many who harvest the highly prized fungus have known deep down for quite some time: the world’s most valuable parasite is disappearing. The culprit is overharvesting with a sprinkle of — what’s by now a usual suspect — climate change.

The fungal ‘gold mine’ is running out

Ophiocordyceps sinensis, known as Yarsa-gumba (यार्सागुम्बा, which is Nepali for “winter worm, summer grass”) is an entomopathogenic fungus that grows on insects, particularly the larvae of moths within the family Hepialidae.

Thousands of people living in Tibet and neighboring Bhutan depend on the caterpillar fungus for their livelihoods. They harvest the fungus and then sell it to dealers that bring it to markets in China. The caterpillar fungus is highly regarded in traditional Chinese and Tibetan medicine, where it’s used as an immune system booster and to treat all sorts of conditions, including cancer.

The caterpillar fungus’ anti-cancer properties have never been proven in a clinical trial. However, there are studies that suggest the fruiting body has some pharmaceutical effects that can be used to treat conditions such as hyposexuality, night sweats, hyperglycemia, hyperlipidemia, asthenia, arrhythmias, and other heart, respiratory, renal and liver diseases. It, at least, does not seem worthless in medicine like rhino horn (Chinese market demand is threatening the iconic animals with extinction). But is it worth its hefty price?

Weighing the precious Caterpillar fungus in Gyegu-Yushu, Southern Qinghai, China. Credit: Wikimedia Commons.

Weighing the precious Caterpillar fungus in Gyegu-Yushu, Southern Qinghai, China. Credit: Wikimedia Commons.

In 2008 the price of C. sinensis was around USD $13,000 per kg, earning it the name “soft gold” in China. As of August 2012, the price rose to USD $111,560 per kg and, according to The Atlantic’s Ed Young, some of the biggest and most attractive pieces can fetch $140,000 per kilogram — more than three times the price of gold.

The global market for “soft gold” is estimated to be worth $5 billion to $11 billion, contributing a hefty chunk of Tibet’s and Bhutan’s GDP. It’s estimated that 40% of the rural cash income in the Tibet Autonomous Region comes from the dark-brown fruiting body, supporting hundreds of thousands of people. But their luck seems to be running out.

Kelly Hopping, an ecologist at Boise State University, interviewed hundreds of collectors and went to the field to gather samples and analyze the chilly Himalayan climate. Reporting in the Proceedings of the National Academy of SciencesHopping and colleagues found that “harvesters increasingly attribute declining production to overexploitation, while models indicate that climate warming is also contributing to this decline.”

“We find that, according to collectors across four countries, caterpillar fungus production has decreased due to habitat degradation, climate change, and especially overexploitation. Our statistical models corroborate that climate change is contributing to this decline,” the authors of the new study wrote.

According to the researchers, the caterpillar fungus grows best at 3,000 to 5,000 meters above sea level, being most comfortable at temperatures of 5 to 20 degrees Fahrenheit (-15 to -5 Celsius). The problem is that the Himalayan winters have been warming up considerably due to climate change, affecting the harvest of the fungus. Although, it has to be said that the fungus is the least of our worries in the case of a warming Himalayas, whose glaciers are often referred to as the ‘third pole’. These glaciers feed the giant rivers of Asia and meet water demand for over three billion people.

Local authorities are aware of the caterpillar fungus’ decline and, in countries such as Bhutan, there are quotas for how much people are allowed to harvest. The hefty price, however, attracts poachers who — just like in the tragedy of the commons — are quick to seize their chance before someone else beats them to it.

If the caterpillar fungus disappears or dwindles to a shadow of its former self, hundreds of thousands of people will be out of work. This will be a huge challenge for Tibet and Bhutan, whose governments will have to find a way to offer new opportunities for many of its poor and untrained citizens.

The Sky Burial

First of all, it has to be said that this once common burial practice in Tibet is pretty hard to ‘digest’ for our ‘civilized’ world, and there’s a big chance you’ll find the pictures shocking. As adepts of Buddhism, Tibetans believe the single most important part of a person is its spirit, and after death, there is no reason to preserve the body, which is just a hollow vessel. Also, wood is very scarce and the soil is really rocky, making it hard to dig a grave. That’s pretty much why, after a somebody dies, the corpse was cut in specific locations and placed on a mountaintop where vultures feed off of it or it just decomposes.

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My first impression when I first heard of it was quite severe; but thinking about it better, it does seem to make sense. I mean, digging a grave would be extremely hard and impractical, while finding enough fuel or wood for cremation would be practically impossible. Also, the spiritual meaning is not hard to understand, when you think outside the western ideology. The deceased is providing food for a part of nature, which is a proof of generosity, one of the most important things in Buddhism.

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The Tibetan name for this ceremony is jhator, which literally means “giving alms to the birds”.

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“Sky burial and open cremation may initially appear grotesque for Westerners, especially if they have not reflected on their own burial practice of embalming. For Tibetan Buddhists, sky burial and cremation are templates of instructional teaching on the impermanence of life.” (unknown)

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It appeared grotesque for the Chinese government too, who prohibited it from 1950 to 1980, and non-Tibetans are allowed to witness this ceremony, though filming or even taking pictures is considered highly offensive. The full procedure is quite expensive, and for those who can’t afford it, simply placing the deceased on a high rock is the favorite option.

The ceremony takes place in light spirit, as the rogyapas (monks) who perform the ceremony talk to each other as when doing any other physical labor. There are different ways to do this; beating the body and bones together to a pulp is not uncommon, while some witnesses reported breaking the bones and cartilages with sledge hammers.

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The vulture in this ceremony is nicknamed the “Eurasian Griffon”, and even with its big appetite, it can’t eat all that it’s being offered, because in some places there are even a few sky burials per day.

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I had some quite interesting talks regarding this ceremony, so please share your opinion on this, it’d be great to see what you guys think about it.

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