Simplify the following text for a Grade 9 native English-speaking person.
Original: One such advancement was ADAM , stem cells harvested from a previously unknown species of sea slug , which were discovered by Dr. Bridgette Tenenbaum to have the ability to regenerate damaged tissue and rewrite the human genome .
Simplified: Scientists also made ADAM , stem cells harvested from an unknown species of sea slug , which were discovered by Dr. Bridgette Tenenbaum to have the ability to heal damaged tissue and rewrite the human genome .