One major difference is that you have to order your DNA typically from a third party provider and they can screen for pathogenic sequences. We could probably stop malware if we could screen all the code before anyone was allowed to run it. I think the current system is reasonably robust for stopping novel syn bio pathogens.
In my mind the big risk comes with home based DNA printers. There are several close to getting to market (eg http://www.kilobaser.com/), at that point we lose control over what gets printed and then maybe there are concerns... though I do think creating a pathogen is really hard and most likely to end up killing the creator before anyone else.
> at that point we lose control over what gets printed and then maybe there are concerns
You have never had control. Perhaps instead you are more worried about our biological weaknesses; there are many! People die all the time from various diseases and even aging. I suggest fixing this before you outlaw DNA manipulation. All of life is a manipulation of DNA in one way or another, and is in fact essential to the maintenance of life... But vulnerabilities should be patched, not swept under the carpet.
It's very hard to Figure out what a random piece of DNA will do just from the sequence. Combine that with other molecular biology techniques for combining, slicing, and dicing DNA, and there would be very little hope to do any sort of prospective screen.
> It's very hard to Figure out what a random piece of DNA will do just from the sequence.
While it's certainly true that it's hard to determine the function of a DNA sequence from scratch, it's considerably easier to compare that sequence (or the sequence of the translated polypeptide) to other homologous sequences to see if it matches something dangerous.
I previously worked in a lab that studied Bacillus anthracis, and we had a bit of trouble getting a major gene synthesis company [1] to produce a plasmid with a variant of atxA [2], and atxA isn't even a toxin, it's just a transcriptional regulator. We presumed that they just BLASTed [3] the sequence we gave them and threw up a red flag when it matched anthracis. So this sort of sequence-checking already occurs.
In my mind the big risk comes with home based DNA printers. There are several close to getting to market (eg http://www.kilobaser.com/), at that point we lose control over what gets printed and then maybe there are concerns... though I do think creating a pathogen is really hard and most likely to end up killing the creator before anyone else.