Miyamoto worked as a member of Team Rocket when it was controlled by a female boss.  She was selected by her boss to hunt out the elusive pokemon, mew, in the Andes Mountains.  After an avalanche she was never heard from again. Miyamoto is also the mother of Musashi (Jessie).  She carries her daughter's picture with her through out her mission.

This unnamed lady (we'll just call her Madame Boss) was the boss of Team Rocket before Sakaki.  Not much is known about her, except that she is the mother of Sakaki as well as his predecessor. Madame Boss was fascinated by the reports of a mythic pokemon known as mew that lived in the Andes Mountains.  She wanted one of these for herself so she sent out one of her subordinates, Miyamoto, to find and capture it.

 
 
 
 
 

Sakaki  (Giovanni in the US)  is the current boss of Team Rocket.  After getting a hold of a fossilized eyelash of the elusive mew, he decided to use it to create the most powerful pokemon ever.  However, Sakaki is a mob boss, not a genetic engineer so he hired Dr. Fuji to create Mewtwo for him.  In exchange for Dr. Fuji's cooperation he was given a laboratory to work in. After Mewtwo destroyed the Research complex he was created in, Sakaki arrived to lure him into Team Rocket with the promise of the world.  However, Sakaki placed to much faith in the "armor" he had equipped Mewtwo with to restrain his power.  After Sakaki told him that he only existed to be a weapon for humans, Mewtwo escaped and blew up Viridian City Gym.

 
 
 
 
 

Dr. Fuji is the skilled geneticist that Sakaki hired to create an incredibly powerful pokemon from the DNA of Mew.  He was in need of a laboratory to continue his research so he accepted Sakaki's offer.  He did not get into genetics to clone pokemon, however.  His true motivation is to create a clone of the daughter he lost in a car accident.  Dr. Fuji was the one who told Mewtwo about mew and how he was created from its manipulated DNA.  Dr. Fuji was blown up along with his research complex during Mewtwo's fit of rage.

 
 
 
 
 

This little girl is actually a clone of the daughter of Dr. Fuji who died in a traffic accident when she was a child.  This technically makes her Ai-two, though she calls herself Ai.  She was fascinated by Mewtwo from the moment she saw him.  She wanted to be like a big sister to him, and in many ways she was.  She shared her knowledge of the world with him, taught him to count, and was his closest friend.  Unfortunately, a clone of a human isn't as viable as those of pokemon.  When Ai-two was four years old she disintegrated, leaving little Mewtwo alone.  He would grow up with not further guidance or even company, left to ponder the same two questions, warping his mind. Ai knew she wouldn't be there with Mewtwo for very long.  The last thing she told him was that he must live.  Not yet aware of death, Mewtwo didn't know what had happened and continued to call out for her, though no response ever came.