Wednesday, April 23, 2014

Scientists cannot afford for DNA science to be eclipsed by DNA technology

In 1986 Renato Delbecco published an article in Science advocating for the sequencing of the human genome. His primary goal was to find a more effective tool in the ongoing fight against cancer. In 2003 the human genome was completely sequenced and the Age of DNA technology was begun. By that time our focus had extended beyond cancer to all diseases with a genetic foundation.

Excitement over what was learned from sequencing the genome has overshadowed what we know about the DNA molecule. One could be forgiven for thinking that the goal in studying the DNA molecule was to map the genome. DNA technology has eclipsed DNA science. As a result no effort has yet been made to determine how this new knowledge about the genome complements other knowledge we have concerning DNA.

Now that we are able to read the instruction book of life an overriding scientific question remains: How does this new knowledge of the genome clarify what we know about DNA?

The sequenced genome can be used in the fight against genetic diseases because it contains the instructions for building an organism. But we should never conclude that fighting disease is our goal. After all, the immune system has been fighting disease long before humans invented medicine. And even if we were to find the answers we seek in DNA technology they can only benefit individual who suffer from or have a genetic disposition to any of those diseases, and only one individual at a time. Given the investment we have made in mapping the genome, it seems reasonable to expect a much broader application that would benefit us all. Thankfully, there is.

An organism does not exist on its own. Each organism belongs to a biological grouping called a species and that species is defined by its DNA. This is widely acknowledged in the knowledge that human DNA is different from feline DNA and from equine DNA. It is not only human individuals who differ from one another by their DNA.

We also know that organisms grow through the process of cell division. When the cell divides the DNA molecule unravels into its two individual strands. Each new cell gets one strand. When the single strand is reconstituted into a new double helix the base pairs are matched using the same matching rule that was in evidence in the original DNA molecule: Cs always pair with Gs and Ts always pair with As. This rule ensures that a cell replicates itself into other cells that look and act in the same way as the original cell. The same rule explains why a man and a woman have a human baby – as opposed to a kitten. DNA does not only govern the growth of an organism; it also governs the growth of the species to which the organism belongs. Whereas only certain traits are considered to be genetic at the level of the individual, as we shall see later, everything is related to the genes or the genome at the level of the species. In essence, no behavior will be observed among a species that is not defined or allowed by that species’ DNA.

The sequenced genome provides us with insight into how DNA determines the traits of each human organism. Those traits depend on the order of the base pairs, hence the need for sequencing. Since each organism belongs to a unique species it follows that DNA also determines the traits of each species. This is scientifically important because a species is not an organization. An organization is formed when separate individuals come together in a group. The sum total of the characteristics of all the parts that belong to the organization determines the characteristics of the organization. By contrast, each species is defined by its DNA and it is this DNA that defines the characteristics of the species. Our inability to study a species except by studying individual members of the species tends to overshadow this scientific fact.

When we study any of the billions of species on our planet we are determining the identity of the species by identifying the properties of its DNA. Because humans are a part of the ecosystem we study our concern with the genome goes beyond our medical desire to overcome genetic diseases but reaches our scientific desire to understand what it means to be human. We would need to determine the sequence of the genome even if we had no diseases with a genetic basis.

The relationship that exists between DNA and the traits of an organism is not the same as the relationship between DNA and the traits that identify the species. But the knowledge the sequences have provided regarding the relationship in the organism is useful in understanding the relationship in the species. And the same use to which this knowledge is put in the organism can be used in the species.

At first this may sound like philosophy or something of even lesser academic rigor. But, because we are dealing with the traits and behavior of a species it is science. Science is a study of our world and our species is a part of our world. More importantly, it is science that crosses all disciplinary boundaries. This is Biology, or Physics, of Chemistry. This is science at its most elemental level. But it directs us not to undiscovered knowledge but to knowledge that has been overlooked. This may be what Dexter meant when he said that “mapping the genome . . . is the outstanding achievement not only of our life time but in terms of human history,” or what Dulbecco meant when he said that “the sequence of the human DNA is the reality of our species, and everything that happens in the world depends on those sequences.

********

Whatever term we decide to apply to this new paradigm, it is well to note how different it is from all the other science we have done. First, it is based on characteristic of the DNA molecule that sets it apart from every other molecule we have studied, and on which current work in DNA technology is not. The DNA is the only molecule that is self-replicating and self-actuating. This means that we are defining ourselves even while we are discovering ourselves.

The human body has not changed over thousands of years. But humans have changed intellectually and socially. The DNA molecule was first isolated in 1869, so ten thousand years ago humans could not be defined as a curious species that is currently studying the genome. This and other cultural changes in our identity have taken place because of the scientific work we have done.

It is becoming clear that our scientific work has been done without consideration of the self-actuating nature of our DNA. We have studied our world from the perspective of explorers. It is now time to review all the work we have done from a new perspective in which we see our species as a single organism and each human being as a cell within that organism. Until we have done work that incorporates this characteristic we have not completed DNA science.

In keeping with Dexter’s comment, the best place to begin is by reviewing the entire process of mapping the genome. DNA technology can do without it. DNA science demands it. I suspect that this is the only way for us to continue our conscious evolution until we eradicate those negative traits that set us apart from all other species. But, unlike other fields of science, one does not have to be a specialist in the field to understand it. Further, because this new approach is concerned with the development of the species as a unit these lessons have many practical applications in the social sciences.

No comments: