DNA Research Shows Modern Humans Benefit From Neanderthal DNA
UNION CITY (CBS SF) -- Recent DNA studies indicate that sexual encounters between Neanderthals and early Homo sapiens may have shaped modern man's health and well-being for generations to come.
The ancient story begins at the tip of the Iberian Peninsula, south of Spain, in Gibraltar.
There, on the sheer southeastern face of the rock, just feet away from the Mediterranean Sea, you find several caves.
Once inside, up catwalks and narrow ladders, archaeologists can be found busy at work, unearthing artifacts from the Neanderthals who once lived there.
While these primitive beings died out tens of thousands of years ago, a growing body of genetic evidence shows they have not vanished.
"Neanderthals are not totally extinct," explained Professor Svante Paabo, a Swedish biologist specializing in evolutionary genetics. Paabo is the director of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany
"Many people are the descendants of Neanderthals," remarked Professor Ed Green. Green runs the Paleogenomics Lab at UC Santa Cruz.
"It changed our view of human history and who we are," exclaimed Professor Rasmus Nielsen. Nielsen is an integrative biologist at UC Berkeley.
What Paabo, Green, and Nielsen are referring to is a shocking discovery in which each scientist participated. Through their scholarship and research, it is clear: many modern day humans are walking around carrying DNA from an extinct people.
The research details how roughly 1 to 5 percent of a person's genome -- whether they are of European or Asian descent -- comes from the Neanderthals.
"It just became assimilated into the human species, they are part of us today," said Nielsen.
"We are all Neanderthals," joked Green in agreement.
In special "clean" labs, like the one headed up by Green at UC Santa Cruz, scientists can extract Neanderthal DNA from tiny bits of fossilized bone.
"It's an amazing thing that we can get DNA our of our ancestors who are now extinct," marveled Green.
He said advances in technology allows experts to quickly sift through and locate ancient DNA.
How did this mashup occur? Chalk it up to a little prehistoric hanky panky. "It came by some Neanderthals and some modern humans having sex," said Nielson.
Half a billion years ago, Neanderthals and the ancient ancestors of modern day humans split.
Then, fast-forward to roughly 50 to 80,000 years, when our ancestors migrated out of Africa. They then encountered Neanderthals who had settled in Europe and West Asia.
As they headed east, our ancient ancestors mixed it up with a distant cousin of Neanderthals called Denisovans. These interactions resulted in children.
Today, modern day humans who are non-African carry traces of these encounters in our DNA
"They affect our health in many different ways," stated Professor Nielsen.
Some Neanderthal and Denisovan gene variants boost our immune systems and help protect against infections.
Scientists think that Neanderthals got exposed to certain pathogens that stoked their immune systems. Our ancestors may have benefited from picking up that gene.
Other gene variants increase the risk of diseases and health issues, including depression, skin problems, allergies, blood clots and even diabetes. As to why, there is some speculation.
To survive under any threatening circumstance that would draw blood, the ability to have a good blood-clotting mechanism would increase the odds of any attack or injury. In times of famine, a variant that was parsimonious in burning energy or a calorie was preferred if there was little food or if you were facing starvation.
However, since modern humans live longer today, blood clots may pose a health issue. And, faced with cheap fast food on every corner and a sedentary lifestyle, modern humans really don't need to hold on to calories.
In addition to these gene variants, there are a few unusual ones that help some of us adapt to extreme environments:
"It could be the high altitude in Tibet, or the cold environment around the Artic," explained Nielsen.
Nielson headed up a recent study that discovered how modern day Tibetans carry a gene variant lifted from the Denisovans
It regulates the molecule that carries oxygen in the blood and allows Tibetans to survive on the Tibetan Plateau, more than three miles above sea level.
"When they breathe, they gets about 60 percent as much oxygen," said Nielsen.
The man who has done the most for the Field of Paleogenomics is arguably Professor Svante Paabo. Paabo is one of the founders of this field. He and his team worked extensively on sequencing or mapping the entire Neanderthal Genome. It was an amazing accomplishment.
Last year, Professor Paabo was awarded the 2016 Breakthrough Prize in Life Sciences for pioneering the sequencing of ancient DNA and ancient genomes and illuminating modern day man's relationship to our extinct relatives.
Paabo played a critical role in the discovery of a new hominin species that we now call Denisovans. He helped to lead a team of scientists who sequenced a tiny finger bone from a young Denisovan girl. The bone, along with some molars, were found in the Denisova Cave in south-western Siberia.
"You want to find out more about our origins and our history and where do we come from if you like," explained Paabo.
That suits Steve Zapiain of Union City. Zapiain joined a research project run by Bay Area's biotechnology and personal genomics company 23andme.
In 2011, Zapiain was diagnosed with a rare blood cancer. The disease is part of a group of similar cancers known as myeloproliferative neoplasms or MPNs. He joined to shed light on the disease and to also help try to find the causes, connections and possible cure.
As part of his participation, he got to explore his own DNA. He was astonished to find out that four percent of his genome is Neanderthal.
"It's cool to be a caveman." laughed the retired school technology director.
Neanderthals were once considered brutes who were clumsy and stupid. Remember the GEICO auto insurance commercials that proclaimed that the company's website was "so easy to use, a caveman can do it?" That notion of Neanderthals is long gone.
"I think that view is really changing," remarked Nielsen.
At the Gibraltar Museum, visitors can see just how remarkable our Neanderthals actually were.
A startling exhibit at the museum features "Nana" and "Flint," two full-size models of Neanderthals created by Kennis & Kennis Reconstructions. The models are based on the forensic reconstructions of the remains of a female and child Neanderthal who were found in Gibraltar.
We now know our ancient Neanderthals relatives had a sophisticated culture, wore clothing, lived in communities, raised families, adorned themselves with feathers, buried their dead --and as seen in one of the Gibraltar caves -- even etched art.
Sometime after they met with the ancestors of modern day humans, Neanderthals suddenly disappeared. No one knows why.
"Was there disease involved? Did we give disease to them that wiped them out? did we actively hunt them and drive them to extinction? Did we just outnumber them?" mused Professor Green.
Now that scientists have the complete Neanderthal genome, their next step is to look for all genetic differences in modern day people to find changes that might hide the clues as to why we survived and they did not.
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