December 6, 2013
700,000-Year-Old DNA Provides Equine Enlightenment
Ever since Charles Darwin proposed his theory of evolution, scientists have been throwing themselves at the Herculean task of demystifying the origins of our modern species. As our technology has expanded, so has our capacity to track the myriad changes that have created the massive variety of species populating our world today. Where once we could only observe and theorize, we now find ourselves privy to all manner of advanced techniques, experimentation, and analyses. Chief among those is the capacity to break down and study the patterns within old DNA strands that manage to survive the test of time. It has allowed for remarkable discoveries, such as the surprising, counter-intuitive hypothesis that suggests an Irish origin of the polar bear.
These 120,000-year-old ursus sequences used to hold the record as the oldest complete genetic sequence uncovered. Such is no longer the case. A recent excavation in the permafrost of Canada’s Yukon Territory has uncovered a strand of truly ancient horse DNA that holds a surprising secret: Equus, the genus encapsulating horses and related equines, is estimated to have been present for 4 million years, double what was previously believed.
The strand of DNA is estimated to be somewhere between 560,000 and 700,000 years old. According to research coordinator Dr. Ludovic Orlando, the decryption was initially thought impossible. However, thanks to the deep-frozen remains and a technique called Single Molecular Sequencing, the team was able to extract what they needed, comparing it with several other samples, ranging from modern domesticated breeds to the more exotic, Asian indigenous Przewalski’s horse. Through these comparisons, they were able to “construct a molecular clock” that can reveal important milestones in the equine’s evolutionary history. This is largely what led them to the earlier conclusion regarding the genus’ elongated background.
It’s no surprise that the next application of this kind of technology is hoped to be connections to us, the good old homo sapiens. If these recent advances and techniques are able to extract DNA more than five to six times older than before, it may very well be able to provide us with even more clues to our own evolutionary background. Obviously, there are some hurdles to face. Not every example of homo genus DNA is going to be as flash-frozen as our frigid equine, nor is there any guarantee that the techniques practiced on the horse were completely error-free. With that said, it does introduce an exciting precedent for DNA strand analysis. The fact that these attempts have produced results at all means that even if the data is not one-hundred percent accurate, we have broken into a new realm of possibilities. As with any new territory, the process may take some time to perfect, but it may not be much longer before we’re able to utilize these very same techniques on our own ancient, long-gone brothers and sisters.
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