Rewriting the Code of Life Possible

Harvard's researchers have developed a genome-scale editing tools and have rewritten the genome of living cells of E. coli  using the genetic equivalent of search and replace. The research that will be published in Science this week was conceived to serve three goals: to add functionality to a cell by encoding for useful new amino acids; to introduce safeguards that prevent cross-contamination between modified organisms and the wild; and to establish multiviral resistance by rewriting code hijacked by viruses.

In this pioneering strategy, the team composed of scientists from prestigious research institutes led by George Church of the Harvard Medical School replaced the sequence of the stop codon TAG of E. coli bacteria into TAA using the multiplex automated genome engineering (MAGE). There were 32 strains constructed that contain TAA codons at every possible way. Through conjugation, the bacterial cells were allowed to transfer genes that contain TAA codons at larger scale. After several rounds of winnowing using conjugative assembly genome engineering (CAGE), the group selected strains with few TAG codons remaining in the bacterial genome.

Four selected E. coli strains were selected and were found to grow healthy and survived even if four groups of 80 codon alterations were conducted in the chromosome, surpassing 1 million base pairs.

See the original news at http://news.harvard.edu/gazette/story/2011/07/editing-the-genome/