Lil' Wayne gave up a DNA sample to prosecutors in a Manhattan court yesterday, evidence the state hopes will link the rapper to an unregistered gun.

As SOHH previously reported, cops nabbed the rapper on gun-possession charges last July when police found an unregistered, loaded .40 caliber Springfield Armory semi-automatic. The gun was recovered inside a Louis Vuitton bag. Cops allege they saw Wayne toss the bag off his lap as they boarded his parked tour bus.

Wayne -- who is pleading not guilty -- swabbed the inside of his cheek with a Q-tip, as he sat on a bench in the hallway of the courthouse, monitored by a detective, according to the New York Post.

He was ordered to give the sample to test his genetic material against that found on the gun.

The sample will take two to three weeks to test.

In related news, Wayne just pleaded not guilty to a separate case in Arizona earlier this month, after being hit with drugs and weapons charges when a Boarder Patrol vehicle search turned up illegal drugs and a .40 caliber pistol belonging to the rapper.