Ah that's my bad, I see it in the top-right corner. The confusion came from having half of the DNA strand be black -- since a lot of the terrain is also black, only the green pops out whenever you have any sort of ceiling above you, so in the beginning of the game I didn't know what the icon meant and didn't notice when it changed (since you grab it and then are expected to die right afterwards). Maybe having it flash white when you pick up a strand to draw your eye to it? It's not a big problem or anything, just my first impression from playing.