Blonde hair, white skin and blue eyes are only indigenous to Europe and found nowhere else. How can it be you have modern humans living in the exact same areas where the blonde, light skin, blue eyed Neanderthal lived and then claim they both developed light skin, blonde hair and blue eyes seperately? Its absolutely ridiculous. Sometimes I think most scientists are idiots that publish rubbish because they have to publish something.
Finally, some scientists have been claiming, its likely that modern Europeans likely got their genes for light hair,skin and eyes from Neanderthals because Neanderthals also had those traits. Absolutely right.
We know which genes cause light hair and blue eyes in humans. And we have high-coverage Neanderthal genomes. As far as I know we do not find the genes that produce light pigmentation in humans in the Neanderthal genome.
Neanderthals probably developed light pigmentation for the same reason humans did -because its an advantageous environmental adaptation in northern latitudes. But separately.