What part(s) of our body are permanent? That is, what parts grow, then never get replaced/recycled/regrown?
If all if it, then we are NEVER the same person from moment to moment in the most literaly sense.
Since we appear to have consistency from day to day, the process must be somewhat slow. What about year to year or decade to decade? Is the process that slow though? If not, how are we consistent across so much time in appearance, personality, habits and such?
DNA likely accounts for much of this, but how much? If none, then where does it come from? If all then the moment we're concieved, we ARE who we are. We may make choices along the way, but those choices are a result of who we are so those choices are determined in the most fundamental sense, the moment we're conceived.
If it's not entirely DNA that dictates who we are, then how much of it is DNA (nature) and how much is otherwise (nurture) and where is that nurture recorded/maintained in ourselves? Our brain? How fast does it regenerate itself? If not at all, then our brain IS who WE ARE. If it regenerates over time, then either that period of time is how often we change OR there's some other part of us that dictates who we are.
Perhaps DNA kickstarts us, our brain is US from day to day, and as it regenerates, it's influenced by who we are (what we do, think, etc..) and so we end up with consistency. In that case, we could halt that consistency up to the point of who we are from our DNA, by interurrupting our decisions and environment completely.
What part of ME is seeking these answers? Why do so many humans seem to have the same quest? Is that explained by DNA or circumstance? If the former, we all are likely to find us here eventually. If the later, some cultures will never ask these questions because they will never come into contact with those who do. How could we know though because if you're asking these questions, you can't go ask others or lead them to the question without putting it in their "minds". It's a bit like (to quote Alan Watts) saying, "Don't think of a pink elephant while taking your medicine." Once heard, one cannot avoid the thought because it's already been comprehended.