Prehistory is considered what time period?

Prehistory refers to the period of time before civilization and writing.

This is the period before human civilizations developed and started writing things down.

Pre means before and history is the record of human events.

The earliest writing systems appeared circa 5,300 years ago but it took thousands of years for writing to be widely adopted. This is why the end of prehistory is very difficult to determine.

The main source for prehistory is archaeology.

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.