Evolving Circuits



Miniaturization may be the name of the game in today’s hi-tech industry, but the truth is that nature is far ahead of human engineers. Dr. Roy Bar-Ziv of the Materials and Interfaces Department at the Weizmann Institute believes the tiniest, most efficient components are already at hand, in the form of DNA, the material of genes. This gift of nature is available for use, if only we can develop biological systems that will do our bidding outside the confines of the living cell.

Bar-Ziv has, in past collaborative work, created DNA-based circuits that function like electronic information circuits. In addition to genes, these circuits run on enzymes, amino acids and a biological energy source. The circuit works when a protein encoded by one gene activates a second gene, which codes for a protein to activate a third gene, and so on. Though slower than a normal electronic circuit, the gene-based circuit has some significant advantages: Billions of molecules could work in parallel in a small space, and the genetic hardware would arrive from the “factory” with the software already installed. In fact, genes are hardware, software and information inextricably rolled into one.

Genetic mutations and the way they drive evolution (in tandem with that other force of nature, natural selection) are the research subject of Dr. Dan Tawfik of the Biological Chemistry Department. Bar-Ziv joined up with Tawfik to see if evolution – which has naturally produced a wealth of highly organized, smart systems – could help create more efficient gene-based circuits. Tawfik had been building simplified artificial cells. When conditions acting on these cells change, they can “evolve” through natural selection. Bar-Ziv and Tawfik plan to create thousands of these rudimentary cells, each containing one of Bar-Ziv’s genetic circuits. Afterward, they will follow their cells to see what changes are wrought in the circuits as a result of natural selection.

Encounter built for two. Dr. Roy Bar-Ziv and Dr. Dan Tawfik














The possible applications are endless. The scientists envision, for instance, biological feedback circuits that will function like automatic fire extinguishers. Rather than sensing smoke in the vicinity, a gene circuit might keep tabs on levels of a substance such as glucose in a system. As soon as levels pass a predetermined threshold (say, in the blood of a diabetic patient), enzymes to break down glucose would automatically be released until the level fell below the threshold limit once again.

Dr. Roy Bar-Ziv’s research is supported by the Sir Charles Clore Prize – The Clore Foundation; the Helen and Martin Kimmel Center for Nanoscale Science; the Philip M. Klutznick Fund for Research; the Levy-Markus Foundation; the Lord Sieff of Brimpton Memorial Fund; Sir Harry Djanogly, CBE; and the Clore Center for Biological Physics. Dr. Bar-Ziv is the incumbent of the Beracha Foundation Career Development Chair.

Dr. Dan Tawfik’s research is supported by the Y. Leon Benoziyo Institute for Molecular Medicine; the Dolfi and Lola Ebner Center for Biomedical Research; the Estelle Funk Foundation; the Dr. Ernst Nathan Fund for Biomedical Research; the Henry S. and Anne Reich Family Foundation; the Harry and Jeanette Weinberg Fund for Molecular Genetics of Cancer; and the Eugene and Delores Zemsky Charitable Foundation Inc. Dr. Tawfik is the incumbent of the Elaine Blond Career Development Chair.