ANSWER: 24-Isopropylcholesterol
Explanation:
MIT researchers have discovered that a rare molecule called 24-Isopropylcholesterol has been found in rocks at least 640 million years old. It is currently produced by sea sponges and a team has tried to find out which gene is implicated for producing 24-IPC, what organisms have this gene and when it evolved in these organisms . Team narrowed it to a single gene called SMT/sterol methyltransferase which causes organisms to produce 24-IPC if it has the correct number of copies. SMT is found in both sea sponge and algae species. Through gene analysis based on fossil record, scientists found sea sponges producing this molecule long before algae.
