Arguably, one of the most important books in the 20th century was Thomas Kuhn’s The Structure of Scientific Revolutions, published in 1962. Before his seminal work, science was believed to move in linear increments. Namely, science progressed in a relatively predictable way as scientists learned more and more. But instead, Kuhn demonstrated that science really progresses through what he called paradigm shifts. Scientists continue along a path until someone comes in and shakes up the prevailing wisdom. A lot of research follows to prove or disprove this radical new hypothesis, and science “leaps” into this new understanding. Kuhn’s model suggests that science progresses through periods of stability (normal science) punctuated by revolutionary upheavals (paradigm shifts). Einstein’s theory of relativity is one example, as he was the first to recognize that space and time were related. This paradigm shift involved a fundamental change in how scientists perceive the universe.
One such interesting paradigm shift in paleontology is described in Nova’s program Hunt for the Oldest DNA.
It tells the story of Eske Willerslev, a Danish scientist studying at the University of Copenhagen. He was interested in the study of ancient DNA, but he was of no importance and couldn’t get ancient DNA samples.
He believed that no one, including himself, would have predicted that he would become a scientist. He characterized himself as a basic failure in school. He was a rebel, a bit of troublemaker and not particularly good at schoolwork.
While pursuing his graduate degree, he was thinking about how to get ancient DNA. And one cold and rainy day he observed a person walking her dog and the dog defecating into the soil (this was before the days of cleaning up after your pet). He wondered what happened to the DNA from the stool when it went into the dirt. Would the DNA remain in the soil?
Excited by his idea, he went over to his professor who was seated with a number of other professors and described his hypothesis. Over guffaws from the other professors, his own professor pronounced it was “the stupidest thing that he had ever heard.”
A rebel, unwilling to be deterred, he pursed this question with ancient dirt from Siberian permafrost. He discovered not just a single animal’s DNA (a wooly mammoth), but at least 12 different ancient animal DNAs and plant DNA as well. A new field was born.
Up until Eske’s discovery, ancient DNA was only available from a minute number of fossils that contained some DNA.
By the way, Jurassic Park is a myth. There is no dinosaur DNA. Dinosaurs were extinguished 65 million years ago. In a most recent study, Eske was able to find identifiable DNA fragments that were approximately 2 ½ million years old. Scientists agree that it is not possible to recover 65-million-year-old DNA.
One major problem with finding ancient DNA is that DNA degrades rapidly. Instead of a full DNA strand, only snippets of DNA remain. Before Eske, approximately 100 pairs had to be recovered to identify a species (we have 3 billion pairs of DNA steps in our DNA ladder). But a technique emerged that allowed him to identify smaller snippets of DNA in dirt. Recently it was discovered that in the soil, certain minerals like clay and quartz bind to the DNA to preserve some fragments.
What makes this particularly relevant for us is that the newly discovered DNA are from the Pliocene era. This is the era before the Ice Age, where the earth was far hotter than it is now. Scientists believe with our CO2 issue that we are headed for a warmer climate that could mimic the Pliocene age.
And the moral of the story? That by using our imagination we can even make dog poop revolutionary.
Angela Rieck, a Caroline County native, received her PhD in Mathematical Psychology from the University of Maryland and worked as a scientist at Bell Labs, and other high-tech companies in New Jersey before retiring as a corporate executive. Angela and her dogs divide their time between St Michaels and Key West Florida. Her daughter lives and works in New York City.
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