Simplify the following text for a Grade 15 native English-speaking person.
Original: In 1997 , Mark Stoneking stated : `` These results ( based on mitochondrial DNA extracted from Neanderthal bone ) indicate that Neanderthals did not contribute mitochondrial DNA to modern humansâ Neanderthals are not our ancestors '' .
Simplified: In 1997 , Dr. Mark Stoneking , then an associate professor of anthropology at Pennsylvania State University , stated : `` These results ( based on mitochondrial DNA extracted from Neanderthal bone ) indicate that Neanderthals did not contribute mitochondrial DNA to modern humansâ Neanderthals are not our ancestors . ''