The mystery religions ​

Mystery religion, any of various secret cults of the Greco-Roman world that offered to individuals religious experiences not provided by the official public religions. They originated in tribal ceremonies that were performed by primitive peoples in many parts of the world.

Explanation, the word mystery is derived from the Greek verb mien (“to close”), referring to the lips and the eyes.

History  

Dionysiac

In every Greek city the god Dionysus was worshipped by fraternities and sororities and also by mixed communities. Dionysus was a god of fruitfulness and vegetation but especially of wine. The Dionysiac festivals provided an opportunity for stepping outside of the daily routine. The festivals included not only drinking wine and engaging in sexual activity but also participating in such significant features of Greek civilization as choral singing and mimes. In many cases, only the initiated could participate in the ceremonies. As almost every Greek did join in, initiation into the Dionysiac cult might be compared to tribal initiations. It seems that initiation into the Dionysiac Mysteries was accompanied by initiation into sexual life.              

orphic  

genetics is the study of how dna works, the methodologies defining the new recent technologies allow scientist to have a panoramic view of the entire dna landscape, especially how genomes interact with their environment, including off course, factors outside their organisms.

thus is very possible the existence of both scenarios, where populations of isolated individuals have different genetic traits, and share traits related to genetic mutation, due rats can easily travel overseas using human transport channels. so scientists could get a vast number of data, including human interaction, evolution of rodents, health development, spread of infections, development of new organisms, how genomes evolve in different environments and so on.