Isolated populations never remain fully isolated. If Aboriginal Australians managed to reach Australia tens of thousands of years ago, it makes no sense to assu

Isolated populations never remain fully isolated. If Aboriginal Australians managed to reach Australia tens of thousands of years ago, it makes no sense to assume that nobody ever followed them. It's far more likely that there was constant low-level contact with Austronesian peoples – even if it didn't occur in every generation or every century. And it's also quite likely that some lost sailors ended up in Australia over millennia, and some of them had children. If the level of contact is low enough, it won't leave any measurable genetic traces. After all, if you go back sufficiently many generations, most of your biological ancestors are not your genetic ancestors.