Mulder and Scully explain to Skinner that they found traces of CGR, or cosmic galactic radiation, on the body of Dr. Solomon Merkmallen, and that it's a type of radiation only found outside the solar system. In reality, the radiation is termed galactic cosmic rays, or GCR, and, while it originates outside the solar system, it is constantly bombarding Earth.
(at around 19 mins) When Mulder and Scully enter the Sandoz residence, they are let in by a landlord. As they come through the front door, a man wearing a flannel shirt and jeans is visible inside a doorway within the vacant apartment. He seems to react when the camera rolls by as if attempting to subtly retreat. The person is not a character or other part of the story.
Scully receives a call in thee New Mexico desert on her cell phone. That would be impossible given the limited range of cell phone towers and phone. Therefore, Scully would not be able to talk to Skinner and learn about Mulder.
Toward the end of the episode, when Dr. Sandoz calls Scully to tell her that he has figured out what the significance of the symbols are (a mapping of the human genome), he clearly mispronounces the word "chromosome" by saying "chromosone." As an accomplished biologist, this mistake would be highly unlikely.