Design and synthesis of a minimal bacterial genome

Science. 2016 Mar 25;351(6280):aad6253. doi: 10.1126/science.aad6253.


We used whole-genome design and complete chemical synthesis to minimize the 1079-kilobase pair synthetic genome of Mycoplasma mycoides JCVI-syn1.0. An initial design, based on collective knowledge of molecular biology combined with limited transposon mutagenesis data, failed to produce a viable cell. Improved transposon mutagenesis methods revealed a class of quasi-essential genes that are needed for robust growth, explaining the failure of our initial design. Three cycles of design, synthesis, and testing, with retention of quasi-essential genes, produced JCVI-syn3.0 (531 kilobase pairs, 473 genes), which has a genome smaller than that of any autonomously replicating cell found in nature. JCVI-syn3.0 retains almost all genes involved in the synthesis and processing of macromolecules. Unexpectedly, it also contains 149 genes with unknown biological functions. JCVI-syn3.0 is a versatile platform for investigating the core functions of life and for exploring whole-genome design.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Artificial Cells
  • Codon / genetics
  • DNA Transposable Elements
  • DNA, Bacterial / chemical synthesis*
  • DNA, Bacterial / genetics
  • Genes, Essential
  • Genes, Synthetic / genetics
  • Genes, Synthetic / physiology*
  • Genome, Bacterial*
  • Mutagenesis
  • Mycoplasma mycoides / genetics*
  • Proteins / genetics
  • RNA / genetics
  • Synthetic Biology


  • Codon
  • DNA Transposable Elements
  • DNA, Bacterial
  • Proteins
  • RNA