Macrolife by George Zebrowski
Have you read the 1979 SF novel Macrolife: A Mobile Utopia by George Zebrowski?
http://www.sffworld.com/brevoff/289.html
And Dougal Dixon's Man After Man: An Anthropology of the Future:
http://en.wikipedia.org/wiki/Man_After_Man:_An_Anthropology_of_the_Future
As for the idea of controlling genetics precisely in 500,000 years, I think he is
far too conservative with the timeline.
