Researchers at The Scripps Research Institute (TSRI) claim to have created the first stable semisynthetic organism with extra bases added to its genetic code. The single-celled organism is also able to continually replicate the synthetic base pair as it divides, which could mean that future synthetic organisms may be able to carry extra genetic information in their DNA sequences indefinitely.
The cells of all organisms contain genetic information in their DNA as a two-base-pair sequence made up of four molecules – A, T, C, G (Adenine, Cytosine, Thymine, and Guanine). Each of these is known as a nucleotide (consisting of a a nitrogenous base, a phosphate molecule, and a sugar molecule) and are specifically and exclusively paired, so that only A is coupled to T and C is coupled with G. These nucleotides are connected in a chain by the covalent (electron-coupled) bonds between the sugar of one nucleotide and the phosphate of the next, which creates an alternating sugar-phosphate "backbone."
The team from TSRI have added two synthetic bases that they call "X" and "Y" into the genetic code of a E.coli carrier organism – a single-cell bacteria – and then chemically tweaked it to live, replicate, and survive with the extra DNA molecules intact.
The paper is available via PNAS:
Yorke Zhang, et al.,A semisynthetic organism engineered for the stable expansion of the genetic alphabet (DOI: 10.1073/pnas.1616443114)
(Score: 0) by Anonymous Coward on Thursday January 26 2017, @10:30PM
If you RTFA, you'll see that the claim to fame isn't that they got the new bases into DNA, that's been done before, it's that they've rejiggered the needed protein machinery to make the bases persist over generations. It doesn't do anything but take up space, yet, but this is the first step.