Basically you seem agree that there is little difference except that selective breeding is done primarily by farmers (which is not 100% true in the context of pet breeding which is what we were originally discussing) while direct genetic manipulation is going to be the purvey of large corporations with all the attendant dangers that come with large corporations.
No, that's not the important part of what he said. A few large corporations may be leading the industry, but that is irrelevant. Genetic engineering is neither intrinsically expensive nor particularly difficult, and it's getting cheaper and easier at a fast pace.
As he said "genetic engineers have made unprecedented changes to organisms by inserting material that in nature would have been extremely unlikely to get there." Conventional breeding mostly just modulates existing traits. Occassionally genes are brought in from closely related species. Mutations affect only a few base pairs and usually have negligible effects.
Contrast this with genetic engineering, which can introduce genes that are totally unrelated to the organism. For example, in the 'BT maize', maize (kingdom plantae) was given a gene from a bacterium (bacillus thurigensis, kingdom monera)! That sort of transfer is essentially impossible in nature, at least in the higher multicellular organisms. About the only spontaneous way to get a foreign gene into the germ line of a higher organism is by breeding with a related species. Genetic engineering can also introduce wholly synthetic genes into an organism.
Genetic engineering is more dangerous because the likelihood of drastic unexpected consequences is much higher than for selective breeding. E.g., if you cross wheat and rye, you don't get any new compounds in new places, you just get a slightly different combination of existing compounds in the same old places. (In fact, wheat + rye = triticale, a valuable plant which combines the yield of wheat with the hardiness of rye.) In the case of BT maize, you are putting potentially megatons of a powerful toxin in places where it has never been before. If BT maize turns out to poison the environment, it will do so on a spectacular scale. In fact, if it turns out to be poison for people *and* it got loose in the 'wild', it would be a disaster for the whole human race (about the only thing worse would be the equivalent for rice).
[spoiler alert] For an exploration of the dangers of genetic engineering, read Zodiac, a novel by Neal Stephenson. It's about a chemical company that develops bacteria that synthesize chlorinated aromatic hydrocarbons (PCBs, whatever). This is a Stephenson book, so of course the bacteria run amok in the world. The tech gimmick is cool and it's very entertaining.
I don't want the world, I just want your half.
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