When the outside world came into contact with the Pitcairn settlement there was one mutineer left, John Adams. There were Tahitian women alive as well who were part of the Bounty story, having been retrieved from Tahiti after the mutiny.
The island did suffer from lack of resources as the population grew. This lead to two migrations. One to Tahiti in 1831 and another to Norfolk Island in 1856. The latter is where many Norfolk Islanders can claim their ancestry from. Some islanders returned from Norfolk and re-settled Pitcairn soon after that migration.
With regards to genetic diversity, there have been many 'outsiders' that have settled and married with islanders. These were often the result of visiting whalers and shipwrecked sailors. You'll find most of the ancestral lines on Pitcairn have a mix of the initial mutineers, their Tahitian wives and outsiders giving genetic diversity.
I can only think in all this remote islanders and how their way of living will be equivalent of the space settlers of the future. Tiny communities almost completely isolated from the rest of human kind, but yet at the same time, having to deal with the rest of the universe.
One of them, Teehuteatuaenoa, gave her account of the aftermath in an interview from Tahiti: http://www.fatefulvoyage.com/pitcairn/pitcairnDJenny.html
More on Teehuteatuaenoa and the history here: http://www.demtullpitcairn.com/teehuteatuaenoa.html
The island did suffer from lack of resources as the population grew. This lead to two migrations. One to Tahiti in 1831 and another to Norfolk Island in 1856. The latter is where many Norfolk Islanders can claim their ancestry from. Some islanders returned from Norfolk and re-settled Pitcairn soon after that migration.
With regards to genetic diversity, there have been many 'outsiders' that have settled and married with islanders. These were often the result of visiting whalers and shipwrecked sailors. You'll find most of the ancestral lines on Pitcairn have a mix of the initial mutineers, their Tahitian wives and outsiders giving genetic diversity.