So we have DNA. This led me to think of its implications, and I thought of three new possible (?) quests:
1) Find your doppelganger
Just try to be in the same location of another player with your very same look. This probably involves tinkering a few tools to locate single features (i.e. same hair, same shirt...). Building more tools adds to your chances of locating the other player more easily.
2) Find your blood brother/sister
This one would work in a similar way, but with DNA strands instead of outside appearaneces. Thus you MUST build the tools, 'cause blind luck won't work... especially because you have to actually touch the other player.
3) Splank your evil twin to oblivion
And what happens when you locate someone who is the OPPOSITE of you, DNA-wise?