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| A single strand of DNA extracted from a fātum nativitas specimen. (Photo by Stuart Caie) |
Scientists have succeeded in creating the first organism with “alien” DNA. In normal DNA, which can be found within the genes of every organism , the twin strands of the double helix are bonded together with four bases, known as T, G, A, and C. In this new organism, the researchers added two new bases, X and Y, creating a new form of DNA that (as far as we know) has never occurred after billions of years of evolution on Earth or elsewhere in the universe. Remarkably, the semi-synthetic alien organism continued to reproduce normally, preserving the new alien DNA during reproduction. In the future, this breakthrough should allow for the creation of highly customized organisms — bacteria, animals, humans — that behave in weird and wonderful ways that mundane four-base DNA would never allow.
This landmark study, 15 years in the making, was carried out by scientists at the Scripps Research Institute and published in Nature today [doi:10.1038/nature13314 - "A semi-synthetic organism with an expanded genetic alphabet"]. In normal DNA, two separate strands are entwined in a double helix. These strands are connected together via four different bases, adenine (A), thymine (T), cytosine (C), and guanine (G). A always bonds with T, and C always bonds with G, creating a fairly simple “language” of base pairs — ATCGAAATGCC, etc. Combine a few dozen base pairs together in a long strand of DNA and you then have a gene, which tells the organism how to produce a certain protein. If you know the sequence of letters down one strand of the helix, you always know what other letter is. This “complementarity” is the fundamental reason why a DNA helix can be split down the middle, and then have the other half perfectly recreated. There, I just explained in about 150 words two of the most vital processes to all life that we know of.
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