Scientific Ideas change not simply our understanding of natural phenomena; they also "resonate far beyond the realms of science." To think about the relationships between genetics and matters such as the components of human nature such as temperament is one thing. However, to tinker with those components by altering genes is something quite different. (Mukherjee, 2016, p. 20)
Before Darwin and Mendel, biology was collecting and classifying. It resembled stamp collecting more than it resembled a science.
With the discovery of the gene, biology has been transformed into the study of the flow of biological information.
"Information flows from the DNA that provides the instructions to build RNA. RNA provides the instructions that build proteins. Proteins ultimately enabled structure and function--bringing genes to life." (Mukherjee, 2016, p. 169) An organism's genome is a kind of database where the information is stored and manipulated.
Biological information matters.
Sometimes an error occurs in the information flow that shows itself as an illness such as sickle cell, a disease that afflicts people of Afro-Caribbean heritage, that was first identified in 1904. In 1951, Linus Pauling and Harvey Itano identified the variant version of hemoglobin found in sickle cell. Five years later, scientists at Cambridge identified the specific difference between the protein chain in normal hemoglobin and "sickled" hemoglobin. The difference is on a single DNA triplet in which the code of GAG has mutated to GTG. Instead of the amino acid glutamate, the amino acid valine is substituted into the hemoglobin chain. "A change in the sequence of a gene caused the change in the sequence of the protein; that warped its shape; that shrank a cell; that clogged a vein; that jammed the flow; that racked the body (that genes built). Genes, protein, function, and fate were strung in a chain: one chemical alteration in one base pair in DNA was sufficient to "encode" a radical change in human fate." (Mukherjee, 2016, p. 171)
What if it were possible to correct the genome and replace the GTG with GAG? A life altering data error could be corrected and a new and perhaps better fate could be imagined.
But until 2012, the idea that genes could be intentionally edited appeared to be impossible.
This changed when Jennifer A. Doudna, a biochemist at the University of California Berkeley, and a colleague Emmanuelle Charpentier (at the Umeå Institute in Sweden) published a technique that made intentional editing of the genome a reality.
Guided by hints from puzzled Japanese investigators in the late 1980 and a related discovery by two French scientists in the early 2000s, Doudna and Charpentier began to study the immune system of a common bacterium and its method of rendering an attacking virus harmless.
Their meticulous investigation found that the bacteria's immune system is constructed as a two part system, "a seeker and a hitman," (Mukherjee's image). Built into the bacterium's genome is RNA encoded with the DNA of the malicious viruses ("like carrying around a permanent image of your enemy"). This is the "seeker." Once the seeker recognizes the presence of a virus, the second element or "the hitman," a protein called Cas9 is released and guided by the RNA sequence, binds to the virus's DNA, where it acts like a "molecular knife" and slices the virus's DNA, rendering the virus harmless.
While the bacterium used this with specific viruses, Doudna and Charpentier realized that they could trick the bacterium's system and that "by substituting a decoy recognition element," they could force the system to make intentional cuts in other genes and genomes." (Mukherjee, 2016, pp. 470-471) Doudna and Charpentier published their technique in Science in 2012 as CRISPR/Cas9.
Since the publication of CRISPR/Cas9, researchers have begun to use the bacterial system to make changes to DNA at exactly the places such changes are desired.
Further investigations that searched for other bacterial gene sequences like CRISPR in the databases at the National Center for Biotechnology Information which contain hundreds of millions of genetic sequences turned up one called C2c2. Investigators at MIT found that when they equipped bacteria with this gene set, the bacteria were able to defend against viruses that do not have DNA, but only RNA, such as the HIV and polio viruses.
This work has created the tools that make it possible to edit the genome of any organism, including, of course, our own: "organisms with genomes" are now capable of editing their own genome. (Mukherjee, 2016, p. 11)
Other scientists agree with other possible answers.
Led by Jennifer A. Douda, a number of scientists have published an article in Science magazine advocating that scientists implement a moratorium on the use of CRISPR-Cas9 and its variants.
The concern is that because the technique is both effective and easy to use that it will be used before ethical and safety issues have been fully explored by all stakeholders.
What was once theory is now doable; "whether we are going to take the dramatic step of modifying our own germline and in a sense take control of our genetic destiny, which raises enormous peril for humanity," as George Q. Daley, a stem cell expert at Boston Children's Hospital describes the dilemma. (Wade, 20155)
The gene as the fundamental unit of heredity and biological information takes its place along with the byte and the atom as scientific ideas that have become central to our cultural, social, and political lives.
Our growing understanding of each of the three shows how shallow is the conception that being acquainted with the conclusions of science is adequate preparation.
Mukherjee, S. (2016). The Gene: An Intimate History. New York: Scribner.
Pollack, Andrew (2014). A Powerful New Way to Edit DNA (2014). The New York Times, March 4, 2014. R
Wade, Nicholas (2015). Scientists Seek Ban on Methods of Editing the Human Genome (2015). The New York Times, March 20, 2015.
Zimmer, Carl (2016). Scientists Find Form of Crispr Gene Editing with New Capabilities. New York Times, June 3, 2016.
Stamp collecting: Ernest Rutherford is alleged to have asserted that physics is the only science. All the others are merely stamp collecting.
Dr. John Holton
Dr. John Holton joined the S²TEM Centers SC in July of 2013, as a research associate with an emphasis on the STEM literature including state and local STEM plans from around the nation.