[2005/04/26] Genes Must Be Expressed in the Right Order
Genes Must Be Expressed in the Right Order 04/26/2005 A team of scientists
in Switzerland made neural cells switch on a transcription factor earlier
during the embryo¡¯s development. The result? Axons (long
branches of nerve cells) refused to grow to the spinal cord and to the
peripheral target. To the mice, this meant they couldn¡¯t feel things
on the skin due to stunted nerves. The paper is published in PLOS
Biology.1 A synopsis of this paper in the same issue
(published April 26) explains why the order of expression is important:
Building an embryo is like building a
house: everything has to be done at the right time and the right
place if the plans are to be translated faithfully. On the
building site, if the roofer comes along before the bricklayer has
finished, the result may be a bungalow instead of a two-story
residence. In the embryo, if the neurons, for example, start to
make connections prematurely, the resultant animal may lack feeling in
its skin. On the building site, the project
manager passes messages to the subcontractors, and
they tell the laborers what to do and where. In the embryo,
the expression of specific transcription factors (molecules that
tell the cell which DNA sequences to convert into proteins) at different
stages of development and in different places controls the orderly
construction of the body. (Emphasis added in all
quotes.)
1 Hippenmeyer, Arber et al., ¡°¡±, Public
Library of Science Biology Volume 3 | Issue 5 | MAY 2005, DOI:
10.1371/journal.pbio.0030159.
This sounds remarkably like the
illustration made in the film Unlocking the Mystery of
Life as an argument for intelligent design. It¡¯s not just
the molecular machines themselves that are irreducibly complex; the ways
they are constructed – the assembly instructions and developmental
processes – are themselves irreducibly complex. Like Jonathan
Wells quips, ¡°what you have is irreducible complexity all the way
down.¡± Undoubtedly the journal didn¡¯t mean to make a case for
intelligent design, but it sure didn¡¯t make a case for naturalism;
neither the authors of the paper nor the synopsis mentioned evolution
once.