In 1995, we reported the DNA sequences for the first two cellular genomes. Nowadays genome sequences, which contain the genetic instructions for an organism, are routinely obtained and deposited in computer databases.
Last week, we reported that this process can be reversed. The digitized DNA information of Mycoplasma mycoides, a simple bacterium, can now be brought to life.
To make this happen, our group of 25 researchers had to decipher this bacterium's set of instructions, synthesize them, and then express them in a recipient cell. Many technical hurdles had to be overcome. But 15 years and $40 million worth of research later, we are able to combine all of these steps and produce synthetic cells in the laboratory.
So what is new and unique about what we did? The process of synthesizing a cell began at a computer. We started with the more than one million letters of genetic instructions for Mycoplasma mycoides, and then made slight modifications to its DNA sequence. First, we deleted 4,000 letters, which removed the function of two genes. We then replaced 10 genes with four "watermark" sequences. These watermark sequences are each over 1,000 letters in length and can be decoded to reveal the names of people, famous quotations and a website address. The entire sequence of DNA letters was then partitioned into 1,100 pieces, and each was synthesized using four different bottles of chemicals that make up DNA. These DNA fragments were designed such that adjacent pieces contained an 80-letter overlap, which facilitated the assembly process by providing unique regions where the synthetic pieces could join.
Source: Wall Street Journal
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