All of life, as we know it, is created from the same four letters: A, T, G, and C in the amino acids that make up DNA. These four letters are arranged in different sequences to for all the diversity of life as we know it on planet Earth.  But what would happen if we could add two more letters to the mix? Imagine adding two new letters to a language that only has four letters: The possibilities are immense.  That’s what biologist Floyd Romesberg at the Scripps Research Institute hoped to accomplish.  Using bioengineering, he and his team has created new and thriving semisynthetic organisms with DNA consisting of letters A, T, G, and C plus new ones: X and Y.

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