In season 4, episode 1 of Black Mirror (titled USS Callister), Jesse Plemons uses DNA from his coworkers and creates virtual "copies" of his coworkers inside his own private virtual world.
I can grasp the concept of using DNA to create a simulated version of a person (physical attributes and even some personality traits). But the "copies" of these characters in this episode also had the memories of the original person (up to the time when they were copied).
In another episode (Black Mirror S3 E4 - San Junipero), something similar was done. Users entered a virtual world as an avatar with all their memories intact. But in San Junipero they had wires attached to their head which did some sort of brain scan (transferring their memories). However, in USS Callister there was no brain scan performed. In fact, the DNA was extracted from a foreign object (such as a used coffee cup or lollipop).
How did the copied characters retain the original's memories?