What Everyone Needs to Know About Genetics

What Everyone Needs to Know About Genetics

"My guess is that the Y chromosome of every living man has spent at least one generation in the testis of a warlord," the Oxford geneticist Bryan Sykes once told The New York Times. One sexually prolific warlord in particular was Genghis Khan, whose Y chromosome is now found in 16 million men in Central Asia. How did that happen? When Khan would conquer a territory, Sykes says, "he killed the men and systematically inseminated the most attractive women."


That is sexual selection on a grand scale, and that is the subject that most interests Sykes, who famously linked modern humans back to common female ancestors in his bestselling book The Seven Daughters of Eve. A subsequent book, Adam's Curse, argued that the male of the human species will become extinct within 5,000 generations. Now Sykes has turned his attention to one of the most genetically interesting places in the world -- the United States, which is the subject of Sykes's new book DNA USA: A Genetics Biography of America

Sykes tells Big Think he set out, Easy Rider-style, to find the ways in which people with African, Native American and European ancestry were linked. The results were often quite surprising. For instance, most African Americans have some European DNA.

This raises an interesting question. What does it mean about your identity when you discover that you are related to another group that you never would have suspected? The truth is simply too disturbing for some people who simply don't want to know. And that is why Sykes has been described as "de Tocqueville with a DNA kit." Sykes, an Englishman, is teaching Americans about who they are.  

That is one of the most significant applications of genetics, but its uses certainly don't end there. Big Think asked Sykes to explain the one thing everyone needs to know about genetics. It turns out he gave us two. 

Watch the video here:

What's the Significance?

According to Sykes, it is too deterministic to say "your genes determine everything you do." But they are "the deck of cards you are dealt at birth." It is your choice as to what to do with those cards. And yet, the DNA that you are made up of does come from somewhere.

While some are not so happy to find out where they came from, Sykes says "I’m very proud of all of my ancestors that have got their DNA through to me, and I think everybody should be, particularly in America. Because all of you have ancestors that took a lot of trouble to get here, whether it was across the frozen wastes of Siberia or more recently on ships from Europe or, unfortunately, ships from Africa against your ancestors’ will."

Of course, genetics doesn't just tell us about the past. It can also help us predict the future. There are major benefits in health care that derive from knowing your genetics.

What do you think?

As science and health care would greatly benefit from possessing everyone's DNA in a database, do you have a moral responsibility to cooperate and share yours?

Image courtesy of Shutterstock

Follow Daniel Honan on Twitter @Daniel Honan

A landslide is imminent and so is its tsunami

An open letter predicts that a massive wall of rock is about to plunge into Barry Arm Fjord in Alaska.

Image source: Christian Zimmerman/USGS/Big Think
Surprising Science
  • A remote area visited by tourists and cruises, and home to fishing villages, is about to be visited by a devastating tsunami.
  • A wall of rock exposed by a receding glacier is about crash into the waters below.
  • Glaciers hold such areas together — and when they're gone, bad stuff can be left behind.

The Barry Glacier gives its name to Alaska's Barry Arm Fjord, and a new open letter forecasts trouble ahead.

Thanks to global warming, the glacier has been retreating, so far removing two-thirds of its support for a steep mile-long slope, or scarp, containing perhaps 500 million cubic meters of material. (Think the Hoover Dam times several hundred.) The slope has been moving slowly since 1957, but scientists say it's become an avalanche waiting to happen, maybe within the next year, and likely within 20. When it does come crashing down into the fjord, it could set in motion a frightening tsunami overwhelming the fjord's normally peaceful waters .

"It could happen anytime, but the risk just goes way up as this glacier recedes," says hydrologist Anna Liljedahl of Woods Hole, one of the signatories to the letter.

The Barry Arm Fjord

Camping on the fjord's Black Sand Beach

Image source: Matt Zimmerman

The Barry Arm Fjord is a stretch of water between the Harriman Fjord and the Port Wills Fjord, located at the northwest corner of the well-known Prince William Sound. It's a beautiful area, home to a few hundred people supporting the local fishing industry, and it's also a popular destination for tourists — its Black Sand Beach is one of Alaska's most scenic — and cruise ships.

Not Alaska’s first watery rodeo, but likely the biggest

Image source: whrc.org

There have been at least two similar events in the state's recent history, though not on such a massive scale. On July 9, 1958, an earthquake nearby caused 40 million cubic yards of rock to suddenly slide 2,000 feet down into Lituya Bay, producing a tsunami whose peak waves reportedly reached 1,720 feet in height. By the time the wall of water reached the mouth of the bay, it was still 75 feet high. At Taan Fjord in 2015, a landslide caused a tsunami that crested at 600 feet. Both of these events thankfully occurred in sparsely populated areas, so few fatalities occurred.

The Barry Arm event will be larger than either of these by far.

"This is an enormous slope — the mass that could fail weighs over a billion tonnes," said geologist Dave Petley, speaking to Earther. "The internal structure of that rock mass, which will determine whether it collapses, is very complex. At the moment we don't know enough about it to be able to forecast its future behavior."

Outside of Alaska, on the west coast of Greenland, a landslide-produced tsunami towered 300 feet high, obliterating a fishing village in its path.

What the letter predicts for Barry Arm Fjord

Moving slowly at first...

Image source: whrc.org

"The effects would be especially severe near where the landslide enters the water at the head of Barry Arm. Additionally, areas of shallow water, or low-lying land near the shore, would be in danger even further from the source. A minor failure may not produce significant impacts beyond the inner parts of the fiord, while a complete failure could be destructive throughout Barry Arm, Harriman Fiord, and parts of Port Wells. Our initial results show complex impacts further from the landslide than Barry Arm, with over 30 foot waves in some distant bays, including Whittier."

The discovery of the impeding landslide began with an observation by the sister of geologist Hig Higman of Ground Truth, an organization in Seldovia, Alaska. Artist Valisa Higman was vacationing in the area and sent her brother some photos of worrying fractures she noticed in the slope, taken while she was on a boat cruising the fjord.

Higman confirmed his sister's hunch via available satellite imagery and, digging deeper, found that between 2009 and 2015 the slope had moved 600 feet downhill, leaving a prominent scar.

Ohio State's Chunli Dai unearthed a connection between the movement and the receding of the Barry Glacier. Comparison of the Barry Arm slope with other similar areas, combined with computer modeling of the possible resulting tsunamis, led to the publication of the group's letter.

While the full group of signatories from 14 organizations and institutions has only been working on the situation for a month, the implications were immediately clear. The signers include experts from Ohio State University, the University of Southern California, and the Anchorage and Fairbanks campuses of the University of Alaska.

Once informed of the open letter's contents, the Alaska's Department of Natural Resources immediately released a warning that "an increasingly likely landslide could generate a wave with devastating effects on fishermen and recreationalists."

How do you prepare for something like this?

Image source: whrc.org

The obvious question is what can be done to prepare for the landslide and tsunami? For one thing, there's more to understand about the upcoming event, and the researchers lay out their plan in the letter:

"To inform and refine hazard mitigation efforts, we would like to pursue several lines of investigation: Detect changes in the slope that might forewarn of a landslide, better understand what could trigger a landslide, and refine tsunami model projections. By mapping the landslide and nearby terrain, both above and below sea level, we can more accurately determine the basic physical dimensions of the landslide. This can be paired with GPS and seismic measurements made over time to see how the slope responds to changes in the glacier and to events like rainstorms and earthquakes. Field and satellite data can support near-real time hazard monitoring, while computer models of landslide and tsunami scenarios can help identify specific places that are most at risk."

In the letter, the authors reached out to those living in and visiting the area, asking, "What specific questions are most important to you?" and "What could be done to reduce the danger to people who want to visit or work in Barry Arm?" They also invited locals to let them know about any changes, including even small rock-falls and landslides.

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Credit: Pixabay
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Credit: Hans Hillewaert via Wikicommons
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