A lone Wraith Scientist conducted experiments to make feeding off Humans more efficient. Violating the wishes of the rest of the Wraith, he tried to make humans more compatible by adding Wraith DNA into their genetic makeup. However, his results found that humans gained the ability to access the Wraith psychic network telepathically. He tried to dilute the effect by returning some of his test subjects to interbreed with other humans, but any amount of DNA was able to give humans access. Worse, many of the subjects went mad and were ostracized from their village. Unable to get around the problem, the scientist gave up. The Wraith eventually learned of his experiments and wiped out the village, but the scientists fate is unknown. (SGA: "The Gift")
Years later, a Wraith Commander named Thorn explained to his daughter, the Wraith Queen Waterlight the story of this Wraith who was her uncle. After the scientist released his subjects for breeding, they spread across a dozen worlds and the Wraith could never locate them. The Wraith in fact came to believe that after five or six generations the "gifts" the scientist gave his subjects would be so diluted as to be unusable. When the Wraith found out, the scientist's own sister stopped him as it was against their old ways. She shut down his testing facility and destroyed his notes, but when he tried again, she was forced to kill him. (SGA: "Inheritors")