In the 1953,
scientists began to unravel the chemistry of life when Watson and Crick proposed a model
for DNA. Soon thereafter the genetic code was broken, and the chemical mechanism behind
evolution became clear. The hypothesis put forth is outlined below:
Sections of DNA called genes store the information needed to make
proteins, and this information is passed from one generation to the next when genes are
replicated during reproduction. The replication process is not perfect, and as such it may
(by chance) introduce errors. Errors during replication (called mutations) have the
potential to create new genes. Mutations may create new information or they may simply
alter existing information. In either case, nature preserves beneficial mutations (through
the process of natural selection) and other mutations survive by chance (genetic drift).
Changes to existing genes over many millions of years yield new genes; therefore, animals
continually evolve and adapt.
Soon after its proposal, this hypothesis became the framework for the
theory of molecular evolution. While scientists have modified it over the years, the basic
framework of the hypothesis remains intact with one important exception.
If an existing gene evolves into a new gene with a new function, then
the original function will be lost, and natural selection will not allow this to happen.
So Ohno suggested that existing genes do not evolve into new genes unless they are first
duplicated.10 The duplicate copy is free to evolve a new function while the original
maintains its current function. Others have refined the theory further by suggesting that
pieces of existing genes may be duplicated and then rearranged to create new genes with
new functions. With these modifications, the molecular theory certainly explains the
origin of many genes.
But even with these improvements, the concern raised earlier remains
the same - why not ask if evolution can happen? Science describes how it happens, but why
not take the next step and investigate the probabilities associated with the required
events. That is rather than assume that naturalistic laws are responsible, prove that
these laws are responsible. This avoids the trap. Thus, experiments are needed to test
whether or not evolution is possible.
A ten year experiment can hardly hope to model a billion years of
evolution, but today there is a solution to this problem. Scientists around the world are
actively sequencing the DNA of many animals, plants and bacteria, and after more than
three decades of characterization, this information is freely available in online
databases. These databases allow science to ask for the very first time two important
questions. Can mutations operating over billions of years and guided by natural selection
create new genes? And perhaps more importantly, are naturalistic laws solely responsible?
Next: Is
Evolution Possible?
Previous: What is Intelligent Design?
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