Could an Alzheimer’s gene make you smarter, and a sickle cell gene make you healthier?

I just read a fascinating article in The New York Times about how genes we think of as bad sometimes do good things too:

“Consider the border between Finland and Russia, where there’s a sharp gradient in the prevalence of autoimmune disorders like celiac disease and Type 1 diabetes. As I’ve pointed out before, these conditions have become worrisomely common in Finland in recent decades, but are between one-fifth and one-sixth as common on the Russian side, despite the fact that the Russians are just as genetically predisposed to developing them.

What protects the Russians from their own genetic inheritance? Or better phrased, what makes the Finns vulnerable?

Finnish scientists think that exposure to a particular community of microbes — one that more resembles the microbiota of our less hygienic past — prevents the diseases from emerging in Russia. That’s important because at least some of the gene variants associated with autoimmune disease are probably useful; they most likely helped us battle infections in the past.

So instead of rewriting our genetic code, a better approach might be to change the interplay between our genes and environment — in this case by altering the microbes we encounter.”

https://www.nytimes.com/2017/06/17/opinion/sunday/crispr-upside-of-bad-genes.html?smprod=nytcore-ipad&smid=nytcore-ipad-share