How do we tell "ghost hominins" in our DNA from just a random mutation of homo sapiens DNA?
I watched a video about ghost hominins aka bits of DNA that seem to divergent, archaic or "weird" to be from just homo sapiens or another hominid we have fossils of (like neanderthals and denisovans) but this gave me a question - how do we define a "human genome"? How do we determine the standard for a modern human with so much genetic diversity? And how do we tell it's not just a random mutation of our species but instead a leftover from mixing with another homo species?