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Feb 21-23, 2003
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An example of this process that took place from 1910 to 1920 is the separation
of the discipline of transmission genetics from the general study of embryology/development
and its more inclusive notion of “inheritance.” A cluster
of scientists working on transmission genetics during the 1920s produced
some ideas of note that shaped later research approaches. H.J. Muller,
for example, published a paper in 1926, “The Gene As the Basis of
Life,” that embraced a “gene-centric” approach that
drew in many other scientists, including Max Delbrück. A.I. Oparin,
by contrast, posited a gradual chemical evolutionary process for the emergence
of life. J.B.S. Haldane, although interested in the latest ideas about
genes, made an early but cogent statement on what are now called “emergent
properties”:
In the present state of our ignorance we may regard the gene either as
a tiny organism which can divide in the environment provided by the rest
of the cell; or as a bit of machinery which the “living” cell
copies at each division. The truth is probably somewhere in between these
two hypotheses….Unless a living creature is a piece of dead matter
plus a soul (a view which finds little support in modern biology) something
of the following kind must be true. A simple organism must consist of
parts A,B,C,D, and so on, each of which can multiply only in the presence
of all, or almost all, of the others.3
Particularly after Watson and Crick announced in 1953 that they had found
“the secret of life,” the double helix structure of DNA, Strick
said, “an overwhelming majority of life scientists…believe
information-carrying molecules more fundamental to life than biochemical
metabolism. This, despite the fact that, ever since researchers have seen
the origin of life to be predicated upon the origin of DNA, RNA, or some
other… information-carrying molecule, the result has been the chicken-egg
problem because of the interdependence of proteins and nucleic acids in
extant cells.”
Two recent books show trends in how scientists have thought about defining
life in the past 40-50 years, Strick said: Freeman Dyson’s 1999
Origins of Life (Cambridge University Press, 2nd ed., 1999) and Maynard
Smith’s and Eors Szathmáry’s The Origins of Life: From
the Birth of Life to the Origin of Language (Oxford University Press,
2000).
Dyson writes about the need to distinguish between replication and reproduction
in order to break what Strick calls “the logical ‘catch-22’
deadlock that results when one considers DNA- or RNA-centered systems
to be the sine-qua-non of life.” Yet Dyson, a physicist, credits
the contributions of such physicists as Schrödinger and Von Neumann
to these studies but ignores the work of biologists, such as Sidney W.
Fox, who emphasized the role of proteins and metabolism in the origin
of life. Fox and his school were later marginalized within the research
community, which was focused single-mindedly on genetic information, Strick
said. “If one is constructing a forerunners’ pedigree for
one’s most important idea, perhaps the temptation is overwhelming
to attribute that idea to winners and silently pass over losers.”
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