The Torah in this week's parsha forbids the mixing of species - Kilayim. This applies to mixing wool and linen in clothes, to crossbreeding livestock, or even to growing many types of crop in the same field.
In a celebrated passage, the Ramban explains the mitzva in the following manner:
And the reason for kilayim is that God created the different species in the world for all the different kinds of souls, in plants and in those that have the animative soul, and he gave them the power of reproduction, that the species should exist for eternity, for as long as He should desire the existence of the world, and He ordered that that power should reproduce the species and never ever change, as is written (in Bereishit) concerning each (species), "l'mineihu" (for its species). And this is the reason that we breed animals in order to preserve the species, just as men come unto women for (the purpose of) reproduction. But one who intermixes two species changes and negates the act of creation, as though he thinks that God did not complete His world sufficiently, and he wishes to assist creation by adding creatures to it.
Amongst animals, different species do not reproduce when mixed, and even those that are naturally close, when they do reproduce, the offspring are unable to reproduce and hence, that line of animals is lost, destroyed. And for these two reasons, the act of mixing species is loathsome and nullified. And plants as well, when they are interbred, their fruit does not grow afterwards, and these two reasons explain their prohibition. (19,19)
It sounds like the Ramban is telling us that creating new combinations and species is, in some manner, destroying God's creation. Our role is to preserve God's creation and teh kinds contained therein. We are not to create new hybrids, new species.
This Ramban has always bothered me. How should we relate to this regarding technological advances? Should we abandon genetic engineering of plants? What about grapefruits, nectarines etc.? Are they not a product of crossbreeding? If we leave creation as it is, then where does it end? Where are the limits of human ingenuity? We know that the Torah allows human involvement i.e. healing or even the manufacture process of food, textiles, household items. But as for Kilayim, do these hybrids not enrich contemporary man?! Or is the Torah warning us that our genetic engineering might undermine and tamper with the very fabric of our world, altering nature to the point of endangering the very foundations of our civilisation?
In today's world we have heard how sometimes, by engineering a plant to become more robust and sturdy to certain bugs or weather conditions, that same crop then dominates over other crops thereby altering and destroying existing ecosystems. Is the Torah already warning us of this problem? The spectre of cloning, of human engineering that is become more and more real in today's scientific landscape is frightening. The warning lights of Huxley's Brave New World and the moral questions of life and death, of man as Creator, these questions go to the very roots of our humanity, our morality.
(In this post, I am of course ignoring the Ramban's Kabbalistic and spiritual overtones regarding the "soul" of plants ... see his comments later in the passge.)
So is new DNA research legitimate development, or is it a reckless foray into the unknown? In this manner, this Ramban raises precisely the conservationist vs. technology debate.
Where is room for growth and change, and where is the room for stability, constancy?