I recently read (in Dawkins' The Ancestor's Tale) about the Alu sequence, and went on to read about transposons generally. Having as I do a rather broad definition of life, I concluded that Alu (and others like it) are lifeforms in their own right, although parasitic ones. I found the potential ethical implications somewhat staggering, especially given the need to shut up and multiply those implications by the rather large number of transposon instances in a typical multicellular organism.
I have written out my thoughts on the subject, at http://jttlov.no-ip.org/writings/alulife.htm. I don't claim to have a well-worked out position, just a series of ideas and questions I feel to be worthy of discussion.
ETA: I have started editing the article based on the discussion below. For reference with the existing discussion, I have preserved a copy of the original article as well, linked from the current version.
Positive feedback exists. You can care about something now primarily because you've cared about it in the past. We even have a name for this: the sunk cost fallacy.
That isn't quite what the sunk cost fallacy means and one can care about something because they cared about it in the past without ever committing the sunk cost fallacy. The sunk cost fallacy requires miscalculating the expected value of a decision to pursue a particular goal due to past expenditure in seeking that goal - ie. behaving as if expenses already incurred are actually anticipated future losses for abandoning the course of action.