The Controversy between Preformation And Epigenesis

Both the preformationist and epigenesist views can be traced back to ancient Greece. The debate between these two points of view reached the climax in the seventeenth and eighteenth centuries. The debate is about whether there is a typical point when life begins or life occurs gradually during the process of development (Maienschein, 2003, Intro). It seems that the epigenesist view has won this debate. However, with the more and more in-depth study in genetics, the debate is far from dead: the genetic inheritance or the environmental impacts, which matters more? Such a debate is different from the previous ones. Also, it has implication in newly-emerged biotech research, for example, the stem cell research. 

The development of biology like modern genetics and biochemistry in the 20th and 21st centuries has brought new concepts to preformationism and epigenesis. The core question of the preformationism/epigenesis debate is whether the individual organism is formed at the very beginning or it forms gradually. Biologists before the 20th centuries over this debate mainly focused on the embryology. Nowadays, the debate is on the scope of gene or genome. In 1910, Morgan’s study in drosophila’s mutation proved that indeed some inherited factors, saying genes, determined the development of organism. The new preformationism came up: genes, “carrying the information necessary to construct an individual”, program the development of organism and environmental impacts have limited influence (Maienschein, 2008). Further genetics studies, for example, Beadle and Tatum’s work on mutants of Neurospora, provided more and more support for this theory. Those studies, especially Francis Crick’s “central dogma” in 1957, made the new preformationist view popular and dominant (Keller, 2000, Ch.2). However, studies in gene regulation and cell differentiation showed that developmental process is not strictly preprogrammed by gene and environmental impacts are of great significance, and such a view is the new epigenesist. Robert Briggs and Thomas King cloned frogs in the 1950s showed cells from early developmental stage could be de-programmed. By the end of 20th century, the adult somatic cell cloning and the stem cell research strongly supported of the new epigenesist view and challenged the prevailing preformationism (Maienschein, 2008). 

The preformationism and epigenesis debate is much more moderate than before. Nowadays debate is about quantity–the genetic inheritance or the environmental impacts, which matters more–while the old debates were about quality—either preformationism or epigenesist. Today, no biologists deny that gene to some degree determines the development nor ignore the environmental regulation of gene expression. On the contrary, they argue which matters more. Some studies, like studies of “Junk DNA” show gene regulates the gene expression itself while others show environmental triggers are crucial in the expression. As study going on, we are likely to get an intermediate view of organism development. “The nowadays of the 21st century may take us back to some of the understanding and insights of the early 20th, a time when a balance of epigenesis and preformationism seemed likely, a time for a bit of predeterminism and a bit of cellular free will” (Maienschein, 2008). 

In a broad sense, the central point in some government policy and public debates over science issues, like cloning and stem cell research, is the preformationist and epigenesist debate. Unlike the pure academic debate, the concepts of preformationism and epigenesis are simplified and such a debate pays more attention on when life begins. For example, in the human embryonic stem cell research debate, the main dispute is about whether an embryo should be considered as a life. Preformationists in this debate think that doing such research equals to murder, thus, oppose it while the proponents hold the epigenesist view that life does not begin at fertilization. Such debate is much more from the ethical view than from the biological science view. Also, although such a debate among biologists is quite moderate, those public debates are very intense and the two points of are quite conflicting (Maienschein, 2003, Intro, Ch.7). 

In conclusion, though nowadays, preformationist and epigenesist debate still exists, it is quite different from it before. The concepts of preformationism and epigenesis have changed. Also, the debate is not only within the biological academic field, but also came into the public and is more about ethical problem. While more and more scientific evidence keeps mildening and neutralizing the preformationist and epigenesist debate, such debate still remains fierce in the public. 

Reference: 
Maienschein, Jane, "Epigenesis and Preformationism", The Stanford Encyclopedia of Philosophy (Fall 2008 Edition), Edward N. Zalta (ed.), URL = <http://plato.stanford.edu/archives/fall2008/entries/epigenesis/>. 
Maienschein, Jane, “Whose View of Live”, Havard University Press, 2003 
Keller, E Fox, “The Century of the Gene”, Havard University Press, 2000