90s TV show (might be a miniseries) about a post-apocalyptic world roamed by savages

Question

The basic story was that there was a medical treatment (maybe a vaccine) that made you live longer and not age, but some people had a different gene that made them revert to a primal human state and become violent.

The humans who had a successful treatment live in a secure city. Each person has a crystal light on their shirt just below the neck. It glows in different colors — red, blue green etc, and you are only allowed to date/marry and have kids with people of the same color, as this will make sure the kids won't have the bad gene. One of the people there had a black color crystal, as he was maybe part savage but not all the way.

This is what I remember from about 25 years ago.

Answer 1

I think you're thinking of Island City as per 90s (or earlier) SciFi movie - glowing lights in chests to indicate attraction

In the future, humanity develops a "fountain of youth" drug, but as many people around the world begin to take it, most begin to mutate into a barbaric proto-humanoid state. The few people immune to this side-effect of the drug band together and live in a futuristic city while the mutants live in the vast wasteland outside its gates.

...

Citizens of the city wore a colored crystal on their sternum and could only mate with other citizens of the same color, which was based on the individual's genetic makeup. Progeny that resulted from breeding outside of your prescribed color would have the genetic mutation that, when combined with the "fountain of youth" drug, created the race of proto-humanoids.

I was pretty sure I'd seen this one before, so I searched on the site for [post-apocalyptic] [story-identification] [tv] and this was one of the entries.