While I am far from an expert, I doubt they are infringing on our patents because their method is different. I must grant you, however, that what they are doing sounds oh so familiar.
I don't thin it infringes on the patent, as the silencing mechanism still involves RNA, not the ssDNA that CYGX has. The use of DNA to produce RNA is nothing new, the new thing about the CYGX work is the enabling of ssDNA production