A meme is an idea, behaviour, or style that spreads by means of imitation from person to person within a culture - often with the aim of conveying a particular phenomenon, theme, or meaning represented by the meme. 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. Memes can be seen as cultural equivalents to genes, in that they self-replicate, mutate, and respond to selective pressures.