In 2010, scientists plopped the genetic material of one Mycoplasma bacterium into another type to create the self-replicating cells shown above. Six years later, they've come out with an even simpler synthetic organism that has fewer genes.
Thomas Deerinck, NCMIR/Science Source
Being able to insert the two man-made letters into DNA, alongside the usual four-letter alphabet, could teach old cells new tricks and lead to better drugs, researchers say.
courtesy of Synthorx
The research team used yeast chromosome No. 3 as the model for their biochemical stitchery. Pins and white diamonds in the illustration represent "designer changes" not found in the usual No. 3; yellow stretches represent deletions.