system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Hair color genetics. I was born with red hair, after 2 years it turned blonde. Now I'm dark blonde with single strands of red and black. Why?

I've been dying my hair red because it looks more natural on me than my actual color...
gpt
Genes turn on and off throughout puberty. The gene responsible for producing eumelanin (causes black hair) probably turn on, or the gene responsible for pheomelanin (causes red hair) probably turn off.