context: Indigenous genetic studies suggest that the first inhabitants of the Americas share a single ancestral population, one that developed in isolation, conjectured to be Beringia. The isolation of these peoples in Beringia might have lasted 10–20,000 years. Around 16,500 years ago, the glaciers began melting, allowing people to move south and east into Canada and beyond. These people are believed to have followed herds of now-extinct Pleistocene megafauna along ice-free corridors that stretched between the Laurentide and Cordilleran Ice Sheets.
question: మొదటి అమెరికన్ నివాసుల జన్యుశాస్త్రంపై అధ్యయనాలు వారి పూర్వీకుల జనాభా గురించి ఏమి తేల్చాయి?
answers: single