I think there should be a ban on "owning" custom sequences of DNA, as it will eventually lead to an accumulation of most of our "biological capital" in the hands of very few companies, which could then effectively control what and how we eat (and many other things as well). Already now most biodiversity has vanished from agriculture, with only a handful of different crop species accounting for more than 99 % of all harvests. This is highly dangerous economically, politically and environmentally.