How do Christians who believe in evolution understand Original Sin?

As I understand, many Christians nowadays accept evolution. There are such Christians in most major denominations and inside these denominations exist different traditions and groups of believers, so I understand that there may be different theories in those traditions for how to combine evolution with Christianity. Those theories may broadly be called Theistic Evolution. There may also be individual ideas which are not part of the teaching of a specific denomination, but are plausible theories in which some of the Christians believe, which I am also ready to explore. Do those who are Christians and accept evolution at the same time, think that there was no Adam and Eve? If so, does this mean that there was no original sin? What are the main modern theories how to understand Original Sin (The idea that the humankind changed after the first sin and that people as children of Adam and Eve bear the consequences of this first sin) when believing in evolution at the same time?