Endogeny

The word endogenous  derives from the ενδογενής, meaning "proceeding from within" ("ενδο"=inside "-γενής"=coming from), the complement of exogenous (εξωγενής exo, "έξω"= outside) "proceeding from outside".

Biology
Endogenous substances are those that originate from within an organism, tissue, or cell. Endogenous retroviruses are caused by ancient infections of germ cells in humans, mammals and other vertebrates. Their proviruses remain in the genome and are passed on to the next generation.

Endogenous processes include the self-sustained circadian rhythms of plants and animals.

In some biological systems, endogeneity refers to the recipient of DNA (usually in prokaryotes). However, due to homeostasis, discerning between internal and external influences is often difficult.

Endogenous transcription factors refers to those that are manufactured by the cell, as opposed to cloned transcription factors.

Geology
All processes that take place inside Earth (and other planets) are considered endogenous. They make the continents migrate, push the mountains up, and trigger earthquakes and volcanism. Endogenous processes are driven by the warmth that is produced in the core of Earth by radioactivity and gravity.

Psychology
An emotion or behavior is endogenous if it is spontaneously generated from an individual's internal state.

Economics and finance
A variable is called endogenous if it is explained within the model in which it appears. For example, in a supply and demand model of an agricultural market, the price and quantity of trade would be the endogenous variables explained by the model; changes in the weather or in consumer tastes would be exogenous variables that might shift the supply and demand curves.

Political science
In political science, something is endogenous if it is actually the result of the action for which it is generally labeled the cause. For example, ethnic violence is generally thought to be caused by ethnic division. However, endogeny would say that ethnic divisions are a result of ethnic violence.