Before revision:  We once speculated that the mechanism of DNA to DNA transcription might be similar to that of DNA to RNA transcription, but now we propose that endonuclease dependent transcript cutout may be a possible mechanism of DNA to DNA transcription, in which a copy of ssDNA fragment (transcript) between two nicks produced by nicking endonuclease is released from double-stranded DNA  region in the genome by an unknown ssDNA fragment releasing enzyme.
After revision:  We once speculated that the mechanism of DNA to DNA transcription might be similar to that of DNA to RNA transcription, but now we propose that endonuclease dependent transcript cutout may be a possible mechanism of DNA to DNA transcription, in which a copy of ssDNA fragment (transcript) between two nicks produced by nicking endonuclease is released from double-stranded DNA (dsDNA) region in the genome by an unknown ssDNA fragment releasing enzyme.