Isn't all synthetic DNA based on natural DNA?
This is not the same as what's been done more frequently for the last long while which was dissecting existing genes from other DNA strands (lets say gene XYZ from a starfish) and introducing it into a bacteria.
Also, this doesn't mean I agree with the new law. I think this motion is even more nonsensical than software patents we face today, and has already handed off all the wonderful innovations that the synthetic biology revolution has to offer to a nation who's pumping loads of cash into this sector: China.