 Sergei Rodin contemplates the origins of the code of life. |
A City of Hope researcher has described how one of the most basic requirements for life — the genetic code — evolved. The work received special recognition as the subject of a commentary featured on the Nature.com home page.
Nature.com is the online home of the prestigious journal Nature.
Though biologists broke DNA’s “code of life” many years ago, they remain unsure of how the code came to be. Sergei Rodin, Ph.D., associate professor of biology, has provided one of the most compelling explanations to date.
Proteins are the basic structural and functional components within all cells. They are the tools — the levers, pulleys and scaffolding — with which a cell accomplishes its workaday tasks.
The basic building blocks of these tools are amino acids. For most every living organism, there are only 20 amino acids that — in the right order and combination — make up every protein an organism needs to survive and grow. The cell strings together as many of these amino acids as necessary and in the order needed to produce the right tool — the right protein — for the task at hand.
The instructions for each protein lie within the cell’s genes, and each gene consists of a special code of three-letter “words” called codons. Each codon represents one of the 20 amino acids a cell uses to build its protein tools. As the cell reads through the chain of codons, it brings each appropriate amino acid into line,
attaching it to the one before and building the protein it needs like an assembly line.
Scientists have long sought to understand how each codon came to represent its amino acid. Many thinkers, such as Nobel laureate Francis Crick, believed it was a random accident of nature.
Rodin, though, has uncovered evidence that the process was anything but random. By analyzing the genetic code in new ways, he found patterns biologists had not yet seen — and determined that nature, through a process of elimination, found the most reliable set of codons possible.
Cells need to minimize the chance of errors when they make proteins, he said. “The
system of codons nature ended up with provides the surest way of reading the code of life correctly,” so the resulting protein functions correctly.
Because his work is theoretical, Rodin does not provide his own laboratory evidence for his work. However, research from other laboratories is beginning to produce results that support his findings, and his hypotheses are gaining more notice, as evidenced by the Nature.com commentary.
In the meantime, Rodin, who collaborates with his son, Andrei, an assistant professor in the School of Public Health at the University of Texas, Houston, continues to delve into these most basic mysteries of biology. As they seek to solidify their arguments about how the genetic code evolved, he and his son are uncovering some remarkable findings.
“We see Fibonacci numbers, and the golden ratio is even apparent,” said Sergei Rodin. Fibonacci numbers, named after the 11th century mathematician who first described them to Western culture, are a sequence of numbers in which each subsequent number is equal to the sum of the previous two. The golden ratio is a mathematical proportion that has fascinated the greatest minds since ancient times.
According to Sergei Rodin, the golden ratio applies to transfer RNA, the molecule that translates the genetic code into protein. “Transfer RNA actually brings the genetic code into action and, therefore, is probably the most important molecule of life,” he said. “That evolutionary shaping of this molecule fits the golden ratio is remarkable.”
Sergei Rodin hopes to publish this most recent work in support of his theories later this year.