The word allelopathy derives from two separate words.
They are allelon - which means "of each other",
and pathos - which means "to suffer".
Plants exhibit allelopathy when one species emits toxic fumes to prevent the growth of another plant species.
Humans exhibit allelopathy - not to be confused with resource competition - when they suppress another group to a life in a toxic environment.
This is how ghettos are formed.
The prevailing culture creates a hostile environment in which another culture has problems existing.
The oppressed culture is forced to move to the less desired parts of town to retain any hope for their survival.
This is also how ghettos are regenerated.
The prevailing ghetto culture creates an environment that is hostile to anyone seeking non-conformity to ghetto ways.
Those seeking to do better for themselves are quickly eliminated in order for the ghetto to continue it's existence.
Who says humans don't emulate the natural world?