One reason to feel like we live in especially exciting times is the news that the world of medicine is currently undergoing something like establishing a new GRIN-type—it is integrating a new type of cell into our bodies!
It all started in 1953: Leroy Stevens, a researcher at Jackson Laboratory in Bar Harbor, Maine, was assigned to test whether cancer might be caused by the paper in cigarettes, rather than by the tobacco. While monitoring the unsurprising lack of cancer in mice who smoke paper, he noticed that a certain family of mice in his laboratory were more likely to have what is known as a “teratoma.” A teratoma is a growth, such as a tooth, a bit of hair, bone, neurons, or even an extra eye or limb in an unusual place. Teratomas have occurred in animals and humans for thousands of years, but only rarely. Stevens began to breed mice to develop teratomas more often and to allow the teratomas to become more and more complex by transplanting them from one mouse to another.
Meanwhile, about 1000 kilometers to the west (and slightly south) at the Ontario Cancer Institute, James Till and Ernest McCulloch were studying the likely consequences of nuclear fall-out by injecting mice with irradiated and non-irradiated bone marrow. Like Stevens, McCulloch noticed strange growths in one of his mice. Just as teratomas have little to do with smoking, these growths had little to do with radiation. By 1961, he and Till determined that each growth was caused by a single cell found in bone marrow. Today, we call the cells they discovered a kind of “adult stem cell.”
By 1970, Stevens determined that teratomas likewise grow from a special type of cell, a type which had been observed before but never identified in adults. Today we call them “embryonic stem cells.” Cells of this type transform into any of the over 200 types of cell a human body may need—that’s why teratomas can get so complex. Adult stem cells also change type, but each adult stem cell has a more limited range of cells it can naturally become. Typically, all embryonic stem cells have become other types by the time an embryo is one week old, but adult stem cells persist into adulthood to serve as a repair system for various parts of the body. One might say that the process of running out of stem cells which can become all types is what limits the human lifespan, since that process gradually reduces the kinds of damage our bodies can repair.
Doctors became excited over the potential to replenish our stem cells. Transplanting stem cells from bone marrow is now standard treatment for certain cancers, as well as for aplastic anemia, congenital neutropenia, severe immunodeficiency syndromes, sickle cell anemia, and thalassemia. In 2008, Paolo Macchiarini of Barcelona successfully transplanted the first organ grown from a patient’s own stem cells: a trachea. Given stem cells with wider ranges, doctors hope to be able to heal all kinds of injuries, treat diabetes, blindness, deafness, Parkinson’s, Alzheimers, Crohn’s disease, arthritis, baldness, and even missing teeth.
By 1981, Martin Evans and Matthew Kaufman of Cambridge and Gail Martin of UCSF had developed techniques to sustain mouse embryonic stem cells in petri dishes, and in 1998 James Thomson of UW-Madison developed a similar technique for humans. Their research was controversial while it involved destroying embryos, but modern techniques do not destroy embryos, and, in 2005, Shinya Yamanaka of Kyoto University engineered the first virus that changes non-stem cells into embryonic stem cells. Rather than take organs or cells from others, we may someday use such methods to trigger our own bodies to grow what we need. Thirty years ago, embryonic stem cells weren’t even stable; thirty years from now, our longevity may depend on them so much that we count embryonic stem cells among the interdependent parts of our bodies.
The story of stem cells points to two ways the GRIN-model could be expanded: First, as Till and McCulloch discovered adult stem cells, one might discover an essential GRIN type that was previously overlooked. Given that some people seem to switch GRIN-type less readily (e.g. Aspies, die-hard conservatives, highly sensitive persons), one leading candidate for a fifth GRIN type would be a person that shifts type to repair teams, families, and congregations as stem cells repair bodies (except that persons, unlike stem cells, might also shift back). Second, as Stevens discovered embryonic stem cells in adults, one might discover a type that was not previously essential to mature societies—perhaps even a type previously dismissed as rare and undesirable, as teratomas were previously dismissed—but demonstrate so much usefulness that society makes it essential.
If you do not identify as a natural gadfly, naturally relational, naturally institutional, or as a natural negotiator, then it may be your nature to become whatever is lacking, you may have a nature which has yet to become essential, or you may have an essential non-shifting nature not yet recognized in the GRIN model. The GRIN Self-Quiz is designed to help determine whether you have an unidentified type, but you may also want to read descriptions of the types and consider whether any sounds like you .
The preceding is an excerpt from Chapter 7 of GRIN Free – GRIN Together: How to let people be themselves (and why you should) by Christopher Santos-Lang.