Your genes are not always your friends

According to a recent publication in the journal Cell, researchers have identified a gene that increases levels of a natural memory-blocking protein.  What? A natural memory-blocking protein!!  It turns out that:

When one protein in our brain (eIF2a) is chemically modified by a memory-blocking protein called Gcn2p, it halts production of genes required for the long-term storage of memories.

By modifying mice to carry instead a version of the eIF2a protein that can't be chemically modified, scientists created supersmart mice that could learn how to navigate mazes twice as fast as other mice!

A natural memory-blocking protein!!??  What's it doing inside my head?  Why would evolution give some people this variant of the gene, and not other people?  Why would scientists have to genetically modify mice to render them (what I would call) normal?

Because not all creatures are the same, even within the same species.  We humans evolved a distribution of traits (or specialization) across individuals.  Not everyone can be smart, because our genes actively prevent some of us from becoming smart!