Drake definitely has a signature sound, it's what made him famous: he sings and raps.
While talking to the JC Online (via HHDX), Drizzy says although rappers had incorporated melodies before, he was the first person to do it successfully. "There were people who incorporated melody before me," Drake said. "but I would deem myself the first person to successfully rap and sing."
Drake has often been criticized as "soft" by the rap community, but he says his persona is not a gimmick. "Yes, there are aspects of it [my persona] that are new in the rap world. But it's not a gimmick. I just sort of exist and people embrace it. I'm one of the few artists who gets to be himself every day. It doesn't take me six hours to get ready and I don't have to wake up in the morning and remember to act like this or talk like this. I just have to be me. That's one of the favourite parts of my life - I've done this purely by being myself."
Read the full interview here, where he talks about performing at bar mitzvahs and "Marvin's Room."