Geneticist
The Geneticist makes his home in the Medical Wing, north of Medbay, but East of Robotics. As a Geneticist, your primary job is to keep essential staff from dying permanently through the use of wacky clone science, while also researching genetic defects and mutations in your spare time. When all the Medical Doctors are dead or incompetent and the Roboticists are too busy putting butts on everyone's heads, it's often the Geneticists that come through with a previous killed crewmate who is able to out the traitor and start a lynch mob. The Genetics lab is frequently an early target of Nuke Agents.
Cloning
To clone someone, you require a scan of their DNA. Either collected while they are still living, or from their recently deceased corpse. To scan their DNA, grab the subject, and put them into the DNA Scanner. Then jump onto the Cloning Console, and Scan them. If their body is still scannable, and the player is still logged in, the scan will be successful. From there, simply 'View Records', and click on 'Clone' under the misfortunate who you wish to bring back to the living.
Once they are out, check with them for toxins damage, and brain damage. Anti-Toxins and Alkysine will fix most problems. Give them a speech on how you are god, let them collect their equipment from their old body, and kick them out. Piece of cake.