Why is a meme compared to a gene?

Context: A meme 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.

Answer: A meme is compared to a gene because it can self-replicate, mutate, and respond to selective pressures similar to that of a gene.