In another reality, Dana Scully might be a brunette instead of a redhead. Anderson told Empire in 2008, her hair “was rat-brown” when the first “X-Files” pilot was shot. Too long before that, however, Anderson received “an executive directive – I don’t know from whom – to make it red.”
In retrospect, the directive may have come from Chris Carter himself, the creator of “X-Files”. Scully is, in part, Carter’s way of paying homage to Clarice Starling, played by Jodie Foster in “The Silence of the Lambs.” In addition to the obvious similarities between their characters, Scully and Starling both have red hair. According to Carter, that is not a coincidence.
The new color definitely suits Scully, but Anderson was never really a fan. “I was a bit shocked at first, because right after the series ended, I got rid of the red as quickly as possible, to try to keep some privacy,” she recalls. However, Anderson wasn’t able to stick with her preferred hair color forever: Given the enduring popularity of “The X-Files,” as well as the need for a revival, she’s back at least red. twice since then.
https://www.slashfilm.com/971158/gillian-anderson-really-didnt-care-for-one-part-of-her-x-files-character/ Gillian Anderson really doesn’t care about that part of her X-Files character