Command against crossing animals, plants and materials

Reading: Leviticus 18:19

This verse intrigues me. This Israelites are told not to let their animals breed with different kinds, not to sow their fields with two different kinds of seed and not to wear garments made of two different materials. I am not sure what God intended by these laws, but it is clear our modern society does not follow them.

If we followed the first there would be no such thing as the mule or the liger/tigon (a cross between a tiger and a lion). Our impacts on the environment have also lead to the creation of more hybrid individuals in the wild, as species who previously never would have come into contact with each other become able to breed. For example, there have been examples of crosses between Polar Bears and Brown Bears because these two species are closely related but until recently geographically isolated enough that they did not cross. Recent changes in temperature and range have made this possible. This does not mean the two species will become one because the offspring of a cross are infertile, but hybrids can experience 'hybrid vigour' ie. they might be stronger or larger than the parents.

These days in the first world we almost do follow the second rule, planting large areas of monocultures for agricultural production. Perhaps this rule was intended to prevent hybridisation of two species as might occur if fields were planted with species. It is interesting however as there is a host of scientific evidence about the fallbacks of monoculture systems and the value of instead mixing species in a polyculture or mixed agriculture system for biodiversity, productivity and disease and pest control. Monocultures are still favoured in large scale operations however as they are simpler to manage and harvest.

As for the final rule - I challenge you to find the single fibre clothing in your wardrobe. Unless this is something you look for, or you spend a lot of money on your clothes, almost everything you own is likely to be a blend of a couple of different fibres. Some people do endeavour to find pure cotton or pure wool clothing, but I think this is more from a dislike for some of the newer fibres and their properties than any belief that single fibre clothing is best.

Does anyone have any clues why God might have made these laws? I would be interested in hearing your opinion.

Finally, I have to mention that these laws have interesting implications for the use of Genetic Engineering/Genetic Modification. I imagine when these laws were written the idea of putting the genes of an Antartic fish into a tomato to protect it from frost were far away, but surely this would not have been counted as kosher?