Create Life From Scratch? It's a Matter of Time
Howard Berg (Physics Today, January, page 24) summarizes an impressive body
of knowledge about one of the simplest living organisms, and refers to
Escherichia coli as a "nanotechnologist's dream." Has a living organism, say
E. coli, ever been made by humans from scratch? To sharpen the question,
have humans ever taken a collection of clearly "dead" ingredients and made a
clearly "alive" organism? Aside from demonstrating technical prowess, would
creation of life in the laboratory be philosophically profound or trivial?
Robert T. Nachtrieb
Massachusetts Institute of Technology
Berg replies: No free-living (independently replicating) organism has been
synthesized from scratch. The possibility of doing so is still remote. The
simplest case, a wall-less bacterium called Mycoplasma, requires DNA
encoding of about 300 genes for growth under laboratory conditions.1 The
functions of about 100 of these are unknown. When isolated from nature, the
species in question, M. genitalium, had 517 genes; compare E. coli at 4288.
But synthesizing the DNA would not be enough: one would need to know what
other components (proteins, lipids, sugars, etc.) are required and how they
might be assembled.
The DNA needed to specify the bacterial virus fX174 was synthesized in 1967
(enzymatically, from a viral template).2 Cells of E. coli exposed to this
synthetic DNA made new virus, giving up their lives in the process. The DNA
of fX174 is a single-stranded circle comprising 5386 nucleotides that encode
11 genes (several overlapping). It was sequenced in 1977.3 The intact virus
is icosahedral, with a protein coat comprising 60, 60, and 12 copies of
proteins specified by genes F, G, and H, respectively. But it was E. coli,
with its machinery for DNA replication and protein synthesis, that made the
Whether creation of life in the laboratory would be philosophically profound
or not depends, I suppose, on one's philosophy. I happen to believe that
life, albeit highly complex, is a matter of physics and chemistry. And I
include consciousness: see Crick.4 So for me, it's simply a matter of time.
However, such a feat would signal an enormous extension of current
understanding. For a timely discussion of broader issues, see ref. 5.
1. C. A. Hutchison III, S. N. Peterson, S. R. Gill, R. T. Cline, O. White,
C. M. Fraser, H. O. Smith, J. C. Venter, Science 286, 2165 (1999).
2. M. Goulian, A. Kornberg, R. L. Sinsheimer, Proc. Natl. Acad. Sci. USA 58,
3. F. Sanger, G. M. Air, B. G. Barrell, N. L. Brown, A. R. Coulson, J. C.
Fiddes, C. A. Hutchison III, P. M. Slocombe, M. Smith, Nature 265, 687
4. F. Crick, The Astonishing Hypothesis, Scribners, New York (1994).
5. M. K. Cho, D. Magnus, A. L. Caplan, D. McGee, The Ethics of Genomics
Group, Science 286, 2087 (1999).
Howard C. Berg
© 2000 American Institute of Physics
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