well I may be pleasantly surprised...
Started reading a book by Alastair Reynolds called 'On the Steel Breeze'.
Only on page 100 of 485 and we have:
a woman who many years ago had 2 clones of herself made. The three were deliberately so similar that even their thought processes were the same and with some enhancements could download each others memories -this was done in a way so that they did not know which was the original.
The three did different things:
One stayed on Earth to be a repository of the memory of all three. However, her son decided to join the merpeople, enhanced humans who live in and under water - land and water humans don't get on...She was so devastated that she had the company that created the clones turn off the memory downloads. a while later the company went into liquidation and all data regarding the three was lost.
Two went in a small spaceship to catch an earlier spaceship that was created by their grandmother who had developed a new mathematics for spaceship engines and decided to test it herself. Two had not been heard of since, until One was contacted by the merpeople who had collected the returned spaceship about 12 years earlier. Two is so close to death, including life support designed to shut down if tampered with, that any attempt to wake her up will just kill her. however there may be enough time to extract the code that would allow One to reconnect memories. the merpeople think that One is being contacted by Three, but due to One's shutting off the memory download the build up of data has become a data being that One sees as a ghost trying to reach out to her.
Three went into space towards another solar system, in a caravan of converted asteroids, hollowed out and filled with biospheres in which millions of people live (partly or largely paid for by one/two/three's family). There is a lot of politics within each and between different holo-ships. The engines were designed by the grandmother - and have reached about 13% the speed of light - unfortunately during the preceding years a flush of scientific development had enabled them to reach this speed, but not develop the ability to slow down when approaching the other system - they had hoped this would be developed later. A scientist in Three's holo-ship had caused a serious explosion while working on the problem and Three had found, in the devastation, a series of tunnels in the skin of the ship that were not part of the maps. Three explored and found the tunnels were only opened by DNA - her families - and once she went further she found a completely hidden biosphere in which live an AI robot, in the physical form of the grandmother and a herd of cognitively enhanced elephants - all illegal.
The AI's memory is not functioning properly because of attacks from a data being called Arachne.
Quite looking forward to seeing where this goes and how he ties the threads together at the end....