The announcement by researchers at the Massachusetts Institute of Technology that they have deciphered a second genetic code is a stunning advance in our understanding of the way biology works. It holds out the promise of important applications in genetic engineering. But it does more than that. It shows again that nature is understandable and that the human mind can unravel its secrets.
The revolution in biology began in 1953, when James Watson and Francis Crick figured out the basic structure and function of DNA. Since then scientists have learned an enormous amount about the chemistry of the genetic code. By the 1960s they had pieced together complete knowledge of the master language by which cells synthesize proteins, the building blocks of life, and how they pass this information from one generation to the next. Within a few years after that they had figured out how to intervene in the process and make changes. Thus genetic engineering was born.
But exactly how the protein synthesis proceeded remained unclear. The overall picture was well known, but a key step in the assembly of aminoacids into proteins was not. The master plan is contained in a cell's DNA. It passes the information on to a substance called messenger RNA, which then gives it to another substance, transfer RNA, which actually puts the protein together.