Simplify the following text for a Grade 7 native English-speaking person.
Original: The first knockout mouse was created by Mario R. Capecchi , Martin Evans and Oliver Smithies in 1989 , for which they were awarded the Nobel Prize in Physiology or Medicine for 2007 .
Simplified: The first knockout mouse was created by Mario R. Capecchi , Martin Evans and Oliver Smithies in 1989 , for which they were awarded the Nobel Prize for Medicine in 2007 .