R.I.P. Janice Voss, a very dedicated astronaut. I was acquainted with Janice. She was a vegetarian like myself. She kept a running list of her favorite scifi and fantasy books. #tips
You mention Neanderthals. What intrigues me is that interbreeding with neanderthals apparently did happen, but the Neanderthal mitochondrial DNA that has been sequenced apparently falls outside the range of human variation.
Does it count if I thought I'd read it but didn't recognize anything when I started to "re-read" it years later, as was the case for LeGuin's The Dispossessed?