This is, by turns,
an important and a frustrating book. It is important because if its arguments
are correct, we need to rethink the notion of the gene, as it has been accepted
in popular and bioethical thought. But it is frustrating because Moss never
really clarifies – perhaps because he cannot yet know – what is really at stake
in the debate. What are the implications, for medicine, for bioethics, and for
environmental debates, if his deflationary view of the gene is correct? The importance of this work turns on these
questions, and these questions are left largely unexplored.

Moss’s primary
concern is the very widespread notion of the gene as a cause of phenotypic
traits, and of the genome as the ‘book of life’ or ‘blueprint’ for the
organism. As a cell biologist turned philosopher, he is very well placed to
assess this concept of the gene. His approach is, initially at least,
historical. George Gaylord Simpson, one of the architects of the modern
synthesis of Mendel and Darwin, famously stated that all attempts to try to
understand the human being prior to 1859, the year of the publication of The Origin of Species, were worthless
and should be ignored. Moss believes that this is false, even if we restrict
ourselves just to biology. In fact, earlier debates in biology played and
continue to play a subterranean influence, in shaping the concepts through
which biologists understand life. We cannot understand contemporary biology,
fully, except by coming to grips with its history.

One of the
perennial temptations in this history has been the idea of preformationism: the
notion that the adult is contained, in
toto and in detail, in the ‘seed’ from which it grows. In previous
centuries, this notion was taken literally: at least some biologists believed
that eggs or sperm contained entire individuals, in miniature, each of which
contained in itself eggs or sperm, which contained entire individuals, and so
on. Preformationism has as its perennial opposition the idea of epigenesis,
according to which more and more complex traits arise during development, in a
manner that is responsive to the local context.

The gene concept
which dominates our discussion today is, Moss argues, the result of the conflation
of two distinct, separately permissible, notions. The first he calls the Gene-P
(for preformationist); the second G-D (for development). A Gene-P is a gene for
a phenotypic trait. But a Gene-P is not
a physical entity. There is a sense in which there are (some) genes for
phenotypic traits, but it is not a simple sense. A Gene-P is not a molecular
entity. Rather, its physical base is the absence
of some molecular entity. Thus, when we say that someone has the “gene for” a
cancer, for instance, we mean that they lack the ability to make a protein.
Since there are indefinitely many ways to lack something, we do not thereby
pick out anything specific at a molecular level. Someone has blue eyes not
because they have the gene for blue eyes, but because they lack the structures
that result in brown eyes, and blue eyes are what human beings have when they
lack these molecular structures.

We can search for
Genes-P by looking at the genome for one of the many variant molecular
structures which people have been found to have when they lack the stretch of
DNA in question, But the variant stretch is not a “gene for” the trait, since
it is not necessarily causally involved in producing it (or at least, not to
any greater extent than a great many other cell structures and stretches of
DNA). Genes-P are not physical structures at all, but predictive devices,
instrumentally defined.

Genes-D, in
contrast, are physical features of the genome, defined by their molecular
structures. But Genes-D are not genes for phenotypic traits. They are one more
developmental resource, among many others. Moss argues that our largely
preformationist gene concept, encapsulated in metaphors like the genome as the
blueprint for the human being, is the result of the illegitimate conflation of
these two senses of gene. There are (some) genes for traits, but they are not
physical entities. There are genes correctly identified with a particular
stretch of DNA, but they are indeterminate with regard to phenotype. The gene
concept foisted upon us is the idea of a gene as a physical entity that codes
for traits. But there is no such gene: no gene is simultaneously a Gene-P and a
Gene-D.

Moss spends much
of the rest of the book defending something akin to the view associated with
developmental systems theory (DST), according to which the genome is not a
privileged repository of information. DST argues that there is no sense in
which genes contain information in which other cellular machinery, and even
environmental influences, do not contain information as well. Moss argues that
the discovery of the Human Genome Project that human beings have far fewer
genes(-D) than predicted is evidence that the complexity of higher organisms is
not a product of their genes. Rather, it is the result of the modular
architecture of organisms as a whole. A long and detailed chapter is devoted to
work on the biology of cancer. Despite all the recent emphasis upon genetic
susceptibility to cancer, Moss argues, the mainstream of oncology is gradually
moving toward a more epigenetic view of its etiology. Genetic mutuations, and
genes(-P) are part of the explanation of the origins of many cancers, but more
important are adaptive, but destabilizing, changes in cells and tissue. Why the
ever-increasing emphasis on genetic screening, in this context, then? Moss has
two explanations. One is the drunk looking for his keys under the lamppost
story: that’s where the light is. Though genes(-P) may be an important part in
the origin of only a small number of tumors, and almost never sufficient by
themselves, at least we know how to look for them. Moreover, genetic screening
can be marketed to patients, and Moss believes that this fact is an important
ingredient in explaining its success.

 What are the implications, for society, for
medicine, and for bioethics if Moss’s attack upon the gene concept is
vindicated? Unfortunately, he is not very forthcoming on this score (though he
obviously believes that the gene concept has been a negative influence, not
only on science but on society at large). Perhaps Moss believes that we cannot
understand the implications, until we have a better grasp of the epigenetic
theory which will replace the gene concept. Nevertheless, we can make a
beginning on drawing the consequences.

If Moss is right,
and the basis of heritable traits lies in many different and interwoven
components of the organism and not in an easily isolable molecule, then the
genetic engineering of particular traits, foretold on all sides, sometimes
welcomed and sometimes condemned, just doesn’t seem to be a technical
possibility. We won’t be designing kids for height or intelligence, not for a
very long time at least and perhaps not ever. If this is right, however, we are
left wondering about the real importance of genetic modification. Consider the
range of genetically altered crops. Are scientists simply mistaken in thinking
that improved yields, or pest resistance, or whatever, is the result of genetic modification? Is this another
example of the preservation of a veneer of Mendelian rhetoric, which is belied
by the actual scientific practice? It has been suggested to me that if DST is
correct, then we no longer have a reason to oppose GMOs. If genes are not the
essence of organisms, then altering them cannot be all that important. Does
this follow?

It is the mark of
an important book that it raises as many questions as it answers: that it
causes us to think again about fundamental issues. To this extent, perhaps the
fact that Moss leaves us with so many questions is a mark of the significance
of his work, and not its limitations. This is far from an easy book (its
appearance in a series entitled ‘Basic Bioethics’ notwithstanding).
Nevertheless, it will repay careful reading, for it may lead us to rethink the
fundamentals of medicine and our approach to it, of reproduction, and of life
itself.

©
2002 Neil Levy

Dr Neil
Levy is a fellow of the Centre
for Applied Philosophy and Public Ethics at Charles
Sturt University, Australia. He is the author of two mongraphs and over a
dozen articles and book chapters on Continental philosophy, ethics and
political philosophy. He is currently writing a book on moral relativism.

Categories: Genetics, Ethics