endogenous

The 30 distinct families of endogenous retroviruses, as that ancient viral DNA is called, in humans each represents a distinct process of colonization.

In rodent studies, sugar consumption has been shown to release chemicals in the brain similar to other addictive substances like alcohol or nicotine, including the release of dopamine and endogenous opioids.

Endorphin is a portmanteau of “endogenous opioid” and in fact drugs like morphine and fentanyl only work in our bodies because they mimic the effects of these innate peptides.

These more advanced forms of silencing ended up regulating the expression of the cell's endogenous genes, leading to the evolution of genomic imprinting.

“They now have the status of villagers, equal to that of the traditional endogenous population settled in the Angkor zone for generations,” the report said.