How much of the world has your DNA seen?
Perched atop the Sierra Nevada mountain range, one can see for miles in every direction. It’s quiet there; nothing much to hear except for the low rustle of wind as it whips over the dirt. Protruding from the desolate landscape are the world’s oldest trees—bristlecone pine trees—at least one of which is more than 5,000 years old1.
Take a moment to let that sink in: 5,000 years old. Five millennia ago, parts of the world were still in the midst of an agricultural revolution as adoption of farming practices swept the globe2. Nearly 5,000 years ago, humans began writing3. 4,000 years ago, written language was being distributed widely as marked by Hammurabi’s code4. Nearly 250 years ago, the United States was born. Just over 40 years ago, the first Star Wars movie was released. And through all of this, the same living tree stood resolute as the world changed around it.
Aside from the bristlecone pine trees, few things on Earth have transcended time like this. The Great Pyramids, the Great Wall of China, and Stonehenge have all been around for at least 2,000 years. But buried in the recesses of our cells sits a biomolecular code that’s been around for much, much longer: DNA.
DNA describes a material in our cells that encodes information used to build life, usually represented by the letters A, T, G, C. For billions of years, DNA strands have been evolving into new and different patterns, eventually producing a combination of patterns that enabled the evolution of human life. Since that time, human DNA sequences have been copied and passed on from generation to generation with very small changes sporadically occurring.
As we did with the bristlecone pine trees, take a moment to process the significance of our DNA sequence being preserved through time. Most of the DNA sequences used to build your body has been around for tens of thousands of years. Where has that DNA sequence been? Did your ancestors—the ones who carried those DNA sequences—live next to the Great Pyramids? What about Stonehenge? This is the question that is being asked when scientists analyze a person’s DNA to determine their genetic ancestry.
On average, the DNA sequence of every human being is about 99.9% identical5. But within that 0.1% difference are clues about our collective history. In the last 200,000 years, human populations have been dynamic, occasionally splitting from one another and assimilating with others. Over this time, small variations in the human DNA sequence became more frequent in some populations relative to others. Some of these variations have survived through generations and live on in modern people. Today, we can analyze someone’s DNA to find remnants of these patterns and use that to tell them where their ancestors may have lived thousands of years ago—well before today’s oldest bristlecone pine trees had sprouted.
Thanks to modern technology, you can learn about the history within your DNA. To be sure, genetic ancestry is not culture, but learning about your ancestors can be a gateway into learning about the many different cultures in our world. Imagine the significance of looking at the Great Wall of China after learning that your DNA sequence has been there before. If your DNA has seen so much of the world, why shouldn’t you?
2“The Development of Agriculture.” Genographic Project, genographic.nationalgeographic.com/development-of-agriculture/.
3Editors, The. “The World’s Oldest Writing.” Archaeology Magazine, http://www.archaeology.org/issues/213-1605/features/4326-cuneiform-the-world-s-oldest-writing.
4“Work Law Code of Hammurabi, King of Babylon.” The Seated Scribe | Louvre Museum | Paris, http://www.louvre.fr/en/oeuvre-notices/law-code-hammurabi-king-babylon.
5“FAQ About Genetic and Genomic Science.” National Human Genome Research Institute (NHGRI), http://www.genome.gov/19016904/faq-about-genetic-and-genomic-science/.