Human beings are multi-cellular organisms. Within seven years from now, every cell within your body will have died and been replaced. Despite this fact, I remain conscious of myself, past & present. Does this suggest dualism? Is memory transfered with DNA? I am reluctant to acknowledge purely materialistic causes since I have not read or heard anything about this kind of data transfer within the body.
So your arm isn't your arm! Whose arm is it?

?? OMG we are walking around in other people's bodies! Thank God Above that He is the repository of all our thoughts and memories, like some celestial data-bank keeper. Without him our memories would never go back furthert than 7 years, and some would not even go that far. And we wouldn't be able to perform intricate physical tasks because the nerve structures would all be different, but with God and dualism all this exists elsewhere so it can rescue us from decay. Except you haven't the slightest idea of how, where and why.
And hang on.... are brain cells replaced? Oh, well, no (though they do die). So where does that leave us after sentence number 2......?
Perhaps a little research into modern neuroscience....?