Dr. Dre and Warren G are steps brothers by marriage. Dr. Dre's mother and Warren G's father married each other and brought both families together.
Warren G was longtime friends with Nate Dogg, who is Snoop Dogg's cousin and he eventually met Snoop and they all started a group called 213, which was named after L.A.'s area code. Dr. Dre ended up meeting Snoop Dogg through Warren G and signed him.
Read: Nate Dogg, Snoop Dogg and Warren G were once in a local rap group called 213
Read: Nate Dogg's vocals on “Regulate” were recorded in a closet due to lack of furniture in Warren G's apartment