In 1993,
researchers at the Scripps Research Institute in California synthetically created a small
sequence of RNA, sometimes referred to as the Scripps molecule, which had some amazing
properties. First, the molecule began to make copies of itself within an hour after it had
formed.
"Secondly,
the copies of this molecule began to make copies of themselves. Finally, these copies
began to evolve and display a variety of chemical properties which had not been
anticipated.
"In
another development, around 1994, Jack Szostak isolated a relatively short sequence of
nucleotides, known as an oligonucleotide, which had catalytic-like properties. This
catalyst could join together other, short sequences or oligonucleotides.
"In
addition, this same catalytic agent could utilize energy from a triphosphate group in
order to underwrite the polymerizing or chaining character of that molecule. This is
important because triphosphates play fundamental roles as suppliers of energy for chemical
reactions taking place in a living cell.
"Other
researchers have proposed alternative routes for, say, the synthesis of RNA
oligonucleotides which could be considered complementary to the previous findings. For
example, James Ferris discovered that montmorillonite, a relatively common clay, is
capable of synthesizing RNA oligonucleotides."
"Dr.
Yardley," said the prosecuting lawyer, "I believe we have covered enough
information to provide the jurors with a good, though necessarily abbreviated, overview of
the evolutionary perspective concerning the origins of life from prebiotic beginnings. If
you were to sum up the general thrust of your testimony, what would you say?"
The
professor stared off into the space near the ceiling at the back of the court room. After
about ten seconds of deliberation, he stated: "If one runs through the available
evidence in support of evolutionary theory, of which my testimony is but a very small
sampling ... if one considers all the cosmological, geological, meteorological,
hydrological and chemical data, then I believe there is only one way to make consistent
sense of the existing evidence.
"Biological
organisms arose gradually, as the result of a series of steps, each of which was selected
by prevailing circumstances that favored such a step over other possibilities existing at
the time of selection. This fortuitous confluence of natural forces required tens of
millions, if not hundreds of millions, of years to complete itself.
"Among
other things, this confluence of forces included various kinds of energy interacting with
the gases in the atmosphere to generate simple hydrocarbons. These hydrocarbons
subsequently precipitated out into a set of hydrological conditions that, perhaps through
a Strecker synthesis process, were conducive to the formation of a sequence of
progressively more complex hydrocarbons, such as amino acids, purines and pyrimidines.
"In
addition, when these complex hydrocarbons were subjected to further processes of
dehydration and condensation in various intertidal zonal regions, then, eventually, a
variety of proteins, nucleic acids, lipids, and carbohydrates formed which were
incorporated into bounded, or membraned micro-environments from which arose the first
proto cells capable of self-replication. This capacity, very likely, was as a result of,
initially, RNA catalytic activity that, at some point, became transformed into a DNA-
based living organism.
"Throughout
the sequence of gradual, evolutionary steps leading from the formation of the Earth, to
the first cellular system capable of self-replication and genetic experimentation,
spontaneous processes of self-organization played important roles. In other words,
although chemical kinetics, the study of the paths and rates of actual reactions,
constitutes an essential part of evolutionary thinking, nevertheless, thermodynamic forces
also spontaneously led to arrangements of energy distribution which had important
evolutionary ramifications for the forms and functions which different molecules came to
have.
"Although
there are certain details of the foregoing scenario which are presently eluding our grasp,
we - that is, evolutionary scientists - believe all of the basic components are, in
principle, now present for a rigorous, consistent, and plausible account of the origins of
life through purely natural processes. Moreover, scientists and researchers, collectively,
are quite confident, despite the fact there may be certain details which currently are
missing from our account, that these same details will be forthcoming in the near future
by virtue of the sort of scientific discoveries which are being made every day around the
world."
"Thank
you, very much, Dr. Yardley," said the prosecuting attorney, "for your
illuminating, expert testimony." As the lawyer walked back to his table, he said:
"Your witness, counselor."
The attorney
for the defense was about to rise, when the judge said: "Mr. Tappin, we are
approaching, if not encroaching on, the dinner hour. Before you start your
cross-examination, I think we will adjourn for meals.
"The
jury is instructed not to discuss these proceedings either among themselves or with anyone
else. Court will be in recess until 7:30 p.m.." With that pronouncement, she banged
her gavel.
