It is amazing how rapidly computer technology is advancing. (Nobody really needed me to point out that fact.) This progress, however, is not open-ended. There is only so much that can be done with silicon-based systems. For example, today’s computer technology will eventually reach an upper limit on its speed of operation.
Some researchers believe that this speed limit can be overcome by carrying out molecular-scale computing. Researchers have determined that molecular computers could operate at speeds that are several orders of magnitude greater than today’s fastest computers. Not only that, this molecular technology could do so with much higher efficiency. So the quest is on to discover and design suitable molecular systems that can form the foundation of molecular computing.
As it turns out, researchers may have found what they are looking for inside the cell. (As I discussed in my book The Cell’s Design, DNA is the ideal molecule for molecular computing.) These scientists engineered a molecular logic gate using DNA and some of the proteins involved in DNA replication.1
For contemporary computers, logic gates convert an input signal into an output. Typically, these outputs are AND, OR, and YES. By using the output of one logic gate as the input to another, computer experts can develop sophisticated networks of gates to compute answers to complex questions. Silicon-based computers use transistors to implement logic gates electronically. But these transistors (which are assembled into integrated circuits) have inherent restrictions on their speed of operation that could be overcome by building logic gates on a molecular scale.
Researchers recognize that the beginning steps of DNA replication also operate as a logic gate—at the molecular level. They were able to modify the biochemical systems involved in DNA replication to engineer AND, OR, and YES logic gates that could respond to chemical inputs provided by scientists in a laboratory setting.
As a biochemist, it’s mind-boggling to me that the routine biochemical processes taking place in the cell can be used to construct computers in a laboratory setting. The direct correspondence between the structure and operation of these cellular systems and those of computers makes these applications possible.
The eerie similarity between logic gates and the structure and metabolism of DNA has profound implications that extend beyond possible technological applications. It can be taken as evidence that life stems from the work of an intelligent Agent. As I argue in The Cell’s Design, the hallmark characteristics of biochemical systems are identical to the features of systems and objects produced by human designers. And by use of analogy, this similarity logically compels the conclusion that life stems from the work of a Designer.
- Thomas Carell, “DNA as a Logic Operator,” Nature 469 (2011): 45–46.