Scientists have created the first stable semi-synthetic organism – a single-celled bacterium – that may play important roles in drug discovery and other applications.
Building on earlier research in which they synthesised a DNA base pair, scientists at The Scripps Research Institute (TSRI) in the US created a new bacterium that uses the four natural bases (ATGC) and a pair two synthetic bases called X and Y in its genetic code.
Researchers have now shown that the single-celled organism can hold on to the synthetic base pair as it divides. “We’ve made this semi-synthetic organism more life-like,” said Floyd Romesberg, professor at TSRI.
Researchers said the work could be used to create new functions for single-celled organisms that play important roles in drug discovery and much more. They had earlier showed that E coli bacteria could hold a synthetic base pair in their genetic code. However, they could not keep the base pair in their code indefinitely as they divided. The X and Y base pair was dropped over time, limiting the ways the organism could use the additional information possessed in their DNA. Therefore the researchers developed the means for the single-celled organism to retain the artificial base pair. They optimised a tool called a nucleotide transporter, which brings the materials necessary for the unnatural base pair to be copied across the cell membrane.
Their semi-synthetic organism was thus able to keep X and Y in its genome after dividing 60 times, leading the researchers to believe it can hold on to the base pair indefinitely.