un-happy purpose to bring others up

From this book, I felt that Powers was exposing everyone's inherent desire to be happy.  We are not all like Thassa, constantly happy wandering through life seemingly untouched by the disasters surrounding us.  We are, I believe, individuals who are in a constant state of un-happiness.  Not sad or depressed or angry, simply not happy - the absence of happiness.  Therefore, we all seek those moments of happiness, regardless of how insignificant or important they may be to us and/or the world in general.  Those that choose to see happiness and joy in the most disastrous circumstances - as an example was shared in our group discussion - are more successful, I would say, in finding those 'moments' that we all strive to find. 

Because Thassa contained the 'happiness gene' and this was tried to be exploited, but in the end failed because of her suicide attempt, Powers is conveying a larger message.  I think he is bringing down science ever so slightly to bring other realms of life up.  Science cannot act alone, but nor can others.  We are all interdependent and this is mainly what I got from this book.