A meme (/miːm/ ⓘ; MEEM) is an idea, behavior, or style that spreads by means of imitation from person to person within a culture and often carries symbolic meaning representing a particular phenomenon or theme. A meme acts as a unit for carrying cultural ideas, symbols, or practices, that can be transmitted from one mind to another through writing, speech, gestures, rituals, or other imitable phenomena with a mimicked theme. Supporters of the concept regard memes as cultural analogues to genes in that they self-replicate, mutate, and respond to selective pressures. In popular language, a meme may refer to an Internet meme, typically an image, that is remixed, copied, and circulated in a shared cultural experience online.
There is a small wormy parasite (Plasmodium falciparum) that attacks our red blood cells (RBCs).
It turns out that people with mutant and half-mutant RBCs are less likely to be attacked by the parasite.
Also, the RBCs of the mutant variety are more likely to be cleared by white blood cells than those that are non-mutants.
Full-blown (homozygous) mutant RBCs kinda suck at their day jobs though.
Whereas half-mutant (heterzygous) RBCs are still mostly functional by comparison.
So being a little weird, but not totally weird, gives an advantage over normies (wild-type) when the RBC parasite is common.
Were there no parasite around, the advantage would go to the non-mutant RBCs because they do their job best. Their downside is being easy targets.
Yeeahh!
Kill Your Lawn, NYT