the final conclusive evidence of Neanderthal DNA within all Europeans was groundbreaking.
We are up to 4% Neanderthal. So we are hybrids after all.
There is much controversy about what Neanderthals gave us....possibly, red hair, blue eyes, pale skin, resistance to certain diseases, depression, autism, high IQ from large brain size, a stoicism to survive in a cold dark climate .... what else ?
Also regarding DNA, i have seen studies where the offspring of Anti-social elements are adopted by some nice law-abiding high achievers. And hey presto, all the biological siblings turned out normal while the adopted kids were anti-social. They grew into copies of their biological parents.....regardless of a good middle-class upbringing. Genes matter.
Separately, i have seen studies of twins separated at birth. And reunited as adults. The similarities in their biography is often uncanny. Hobbies, pastimes, choice of profession, even body-language.