First of all, let me assure that after having lived with it for 10 years and providing the at home death my husband wanted, I consider it a terrible thing. However, I was talking in the very cold blooded terms of survival of the fittest. A family that does not have to feed an elderly, soon to be useless, member has a greater chance of surviving. My husband had many of what are considered to be Neanderthal traits. I would not be surprised if he was more than 4%. Even though he could not remember for more than 15 or 20 seconds, we build a cabin together, he loved to rake the leaves off the moss, and sweep the sidewalk in front of the house. I can imagine an elderly Neanderthal still able to use his flint knapping skills or scraping a hide and thus being useful to the tribe even with Alzheimers. His genetics also included a large amount of northern Scottish, and 1/16 Canadian Indian. And he was what is called a “ginger”.
The time when my husband’s wandering became especially strong was a year or two before he went into serious, burdensome physical decline. In that period he was out sweeping the sidewalk, disappeared, and when I called the police they found him more than 1/2 a mile away still sweeping. Last time I let him out. He would also wake up at 4 am and want to go out and walk the city streets. Fortunately, he could not get out of the bedroom with the attached bathroom, and I always managed to wrestle him back into bed. I forgot to include the link to the comment which you answered. Here it is. Getting older, but no Alzheimers. ;-)
www.archaeology.org/issues/161-1501/features/2787-israel-neanderthal-epigenome-decoded
But doesnt the article say that Neanderthals did not have the predisposition?
“Many genes associated with diseases—in particular psychiatric and neurological disorders such as Alzheimer’s disease, autism, and schizophrenia—also appear to be activated in modern humans but not Neanderthals. Carmel says the activation of these genes may have produced an evolutionary catch-22: bestowing a benefit, perhaps by changing the wiring of our brains, but also introducing an increased risk of disease.”