Epigenetics of Reproduction in Animals - Building the Most Complex Structure on Earth - page 63

Since at the heart of biological reproduction is the information that is used to
erect the tremendously complex multicellular animals, I will first present a concise
description of the nature and origin of biological information invested in the erection
of animal structures.
Biological Information
Information is a term that has different meanings in different disciplines; there is no
generally accepted definition universally applicable to all of them. The American
mathematician and engineer Claude Elwood Shannon (1916-2001) pointed out:
“It is hardly to be expected that a single concept of information would satisfacto-
rily account for the numerous possible applications of this general field” ( Shannon,
1993 ). In communications theory, there is no difference between a meaningful mes-
sage and a nonsensical form of the same message; the number of bits transmitted is
what matters primarily. This is not the case with biological information.
For many centuries, from antiquity until modern times, people believed that life may
arise spontaneously and rather quickly from inorganic matter. Aristotle generalized the
concept of the spontaneous generation in History of Animals ( ca . 355 BCE), where he
wrote that animals may not only arise from their parents but also “grow spontaneously
and not from kindred stock; and of these instances of spontaneous generation some
come from putrefying earth or vegetable matter, as the case is with a number of insects,
while others are spontaneously generated in the inside of animals out of the secretions
of their several organs.” The theory of spontaneous generation prevailed among biolo-
gists in Europe until the seventeenth century and continued intermittently until the
middle of the nineteenth century. With the advent of the scientific method in the sev-
enteenth century, the hypothesis was put to the test by the Italian physician Francesco
Redi (1626-1697), who in 1668 succeeded to experimentally refute the hypothesis
of spontaneous generation. After biologist John Needham (1713-1781) revived the
hypothesis in England, Louis Pasteur (1822-1895), by demonstrating that fermentation
is caused by growth of microorganisms, rung the death knell of the hypothesis.
From the modern biological view, spontaneous generation encounters an insuper-
able difficulty: how can the de novo emerging organisms instantaneously acquire the
huge amount of information for erecting their complex multicellular structure? Even
when constructing a simple Lego structure, some instructions or information on what
has to be built is necessary; it cannot arise by piling its building blocks randomly.
Building a unicellular organism of millions of molecular and supramolecular build-
ing blocks requires an incomparably larger amount of information than a Lego unit
does, and several orders greater amount of information would be required to erect
a multicellular organism. Structures with such a small probability of arising spon-
taneously are known as improbable structures , and no improbable structure, be it a
Lego, a car, a cell, or a multicellular organism, can arise spontaneously. Investment
of some sort of information on how to build them is a prerequisite. The counterargu-
ment that, theoretically at least, improbable structures can arise spontaneously once
(or even twice) in the case of living organisms is invalidated by the fact that these
structures arise regularly in the process of the reproduction of living beings.