Page 244 - The Manga Guide to Biochemistry

Recombinant DNA techniques developed after it had been clearly demonstrated that
DNA is the genetic language (or, in other words, that the information referred to as genes
is written in the form of base sequences in DNA). Molecular biologists imagined that if they
only had the DNA base sequences and if they only created an environment in which proteins
could be created from those base sequences, they could elucidate the phenomena of life,
which can be thought of as the totality of chemical reactions in which proteins are involved.

For example, if genes from an external source are introduced into a simple, easy-to-
manipulate organism for which these mechanisms are well understood (such as E. coli ) to
create proteins within that organism, a large quantity of proteins can be obtained all at once
without ever having to perform any more “dirty work.”

Generally speaking, this idea can be expressed as: Explain the DNA sequences!
Explain life!

Molecular biology has developed with this aim. The methodology used to achieve this
was based on recombinant DNA techniques.

Returning to Biochemistry

After the Human Genome Project (an international cooperative research project aiming to
sequence the genetic information of humans) was completed in 2003, researchers turned
their attention from DNA back towards proteins and RNA.

The post-genome era, or post-sequencing era, arrived.
No matter how much DNA steals the limelight, no matter how its handling techniques
develop, and no matter what anyone says, when life phenomena are viewed as a collection
of “chemical reactions,” the only things at work there are proteins and RNA.
This is because, even if all of the base sequences of human DNA (that is, the entire
genome) are known, the data is meaningless unless the roles of the proteins and RNA that
are made from DNA are understood.
Currently, if the amino acid sequences of many proteins are known and the role they
play is also understood, then the work of unknown proteins can be predicted to a certain
degree based on only amino acid information.
However, the role of unknown proteins must be verified by using biochemical tech-
niques. No matter how many molecular biological techniques (such as DNA recombination)
are used to research the activity of proteins to elucidate their roles, the question of whether
or not those proteins really do those jobs inside natural cells will remain unanswered. In a
manner of speaking, this is the same as the idiomatic expression “you can’t see the forest
for the trees.” As long as the research target is a biological substance, biochemistry remains
an absolutely necessary and important academic discipline.

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