Personal reflections

Dr. King's home page | List of publications

Epilogue (autobiographical notes)

For most of my academic career, I aspired to little more than a position that would utilize my academic ability while providing a reasonably peaceful and secure situation for myself and my family. Along the way I simply pursued interesting projects that appeared in my path. Yet every project and manuscript emerged from interests developed earlier in my life, as described below.

I am indebted to my parents, to my many teachers, and to my wife, all of whom encouraged and supported pursuits which eventually led me across fields of neurobiology, histology, fly anatomy, and evolutionary genetics. I also acknowledge with gratitude my academic ancestors beyond those mentioned individually below. My academic family tree can be found by entering my name, David G. King, into the search box at Neurotree.org. Surprisingly (at least to me) it takes only seven person-to-person steps to connect me with Thomas Henry Huxley!

The autobiographical narrative below is offered to suggest some of the circumstances that led me into my career. Additional background detail can be found in my annotated list of publications. I have written these self-indulgent ramblings primarily for myself; I have no idea who else, if anyone, might care.

I sang of leaves, of leaves of gold, and leaves of gold there grew:
Of wind I sang, a wind there came and in the branches blew. . .
O Lórien! The Winter comes, the bare and leafless Day;
The leaves are falling in the stream, the river flows away.

Galadriel's Song
The Fellowship of the Ring
J.R.R. Tolkien

Nature study and insects | Ecology | Neuroscience | Histology

Genetics | Evolution | History and philosophy

Nature study and insects

"The Child is the father of the Man," William Wordsworth.

I grew up in Knollwood, a suburban neighborhood within a mostly-rural county near Dayton, Ohio. (My father and my father-in-law were both employed nearby at Wright-Patterson Air Force Base.) As a very young child, before entering grade school, I had already recognized "nature" as my principal interest. When asked what I wanted to be when I grew up, I would answer, "naturalist."

At age eight my parents enrolled me in the Junior Naturalists program at the Dayton Museum of Natural History, under the sensitive guidance of Edith Blincoe, whose book Nature Walks with Edith Blincoe sits on my bookshelf today.
I was soon enthusiastically collecting insects. That's me at age 14, with a few of my carefully-mounted specimens. Within a couple years I had transitioned from collecting to photography. Annual visits to my paternal grandmother's farm in western Kentucky provided opportunities for exploration and discovery, of toads and tumblebugs, crayfish castles and mud-wasp nests.

At Audubon State Park in Henderson, where my father's cousin King Benson was park naturalist, I was enchanted by a display of exotic insects housed in the park museum's splendid round tower (at left).

Family car trips to national parks (Great Smoky Mountains, Everglades, Mesa Verde, Rocky Mountains, Yellowstone, Tetons, Dinosaur, Carlsbad Caverns) greatly enriched my exposure to wild nature. Every summer, my family would also spend a week in a cabin at Lake Hope State Park in the hills of southeastern Ohio (image at the top of this page), which was a favorite venue for collecting and photographing insects (including fireflies) as well as for learning from park naturalists.

By my early teens, I had begun reading classic nature writers: Henry David Thoreau, Charles Darwin, John Burroughs, John Muir, Jean-Henri Fabre, Edwin Way Teale. I also spent many hours bicycling for miles around Greene County, among farms and woodlots and across covered bridges. Glen Helen and Bryan Park were favorite destinations for picnics and nature walks. (At least as recalled through the mists of nostalgia, Greene County has for me somewhat of the character of the Shire surrounding Hobbiton, which may help explain my later fondness for the writings of J.R.R. Tolkien.)

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Ecology

In biology class at Beavercreek High School, I learned that the scientific discipline which most closely aligned with my nature-study interest was called "ecology." During summer after my junior year (1965), my parents sent me to participate for ten weeks in an ecological research program, sponsored by the National Science Foundation, at the Mountain Research Station of the University of Colorado's Institute of Arctic and Alpine Research. Weekdays called for working high above timberline, assisting with a floristic survey of the tundra on Niwot Ridge (at left). Weekends were free for ad lib tramping about the surrounding landscape.

I am profoundly grateful not only for the ecological research experience but also for such a grand opportunity to hike in the mountains of Colorado. A literal feet-on-the-ground highpoint for my entire lifetime was standing at 13,409 feet on the summit of Navajo Peak (right). During this long summer I discovered that ecological fieldwork could suppress simple, contemplative appreciation of nature. So that wild nature might remain primarily a setting for recreation, I concluded that I might prefer a career of indoor labwork in some other area of biology. (Decades later, in 2008, I did attend a professional ecology conference in Kansas City, where I felt rather out of place.)

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Neuroscience

Yet already in high school, even while pursuing my interest in ecology, I chose topics in neuroscience for two term papers. One of these topics, "Neural processes involved in vision," was prompted by an article in Scientific American (November 1963), written by future Nobel Prize winner David Hubel. I was fascinated that neurophysiology could reveal the information-processing abilities of individual cells in visual cortex. A couple years later at Purdue, while reading The Machinery of the Brain by Dean Wooldridge, I began to imagine neuroscience as a plausible field for graduate study. When Hubel's colleague Torsten Wiesel visited Purdue for a seminar, I was disappointed to learn that Hubel and Wiesel's laboratory did not train graduate students.

My neuroscience mentor at Purdue, Prof. Gopal Das, arranged financial support from the NSF for a summer project under his guidance, preparing and examining histological sections of rat cerebellum. That experience conferred on me a distinct disinterest in histological protocols. I was much more intrigued by the behavior of living nerve cells, such as those Prof. Hubel had described in Scientific American. After reviewing a catalog of neuroscience graduate programs around the country, I applied to the newly-organized Department of Neurosciences at the University of California San Diego. The diverse faculty in this department could provide opportunities for exploring several different specialities, including cellular neurophysiology. This choice proved fortuitous, not least because at this institution "one of the major revolutions in neuroscience" was underway.

After finishing the coursework required for graduation from Purdue with a major in biological sciences, I had intended to indulge in a few elective courses such as entomology. But since all my requirements had already been completed, Purdue pushed me out after seven semesters rather than the usual eight. So, upon receiving my B.S. degree in January of 1970, I headed west with my new wife toward the UCSD campus in La Jolla. Neither of us had ever seen the Pacific Ocean.

Aplysia californica
Image from Wikimedia Commons

During my first graduate school "rotation" in Prof. Ted Bullock's laboratory at UCSD, I was assigned to record electrical potentials from one specific nerve cell in the abdominal ganglion of Aplysia californica, the California "sea hare." I had first encountered Aplysia at age 14, in the pages of Darwin's Voyage of the Beagle. But I hadn't imagined that in just a few years I would be hunting for these marvellous molluscs in California tidepools. I was astonished to learn that unique individual nerve cells could be readily located and identified in this animal. But I also discovered that I really had no affinity for the technology of neurophysiology.

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Histology

I was pulled back toward histology during another rotation, spent mostly overseas in Prof. Paul Glees' laboratory at the University of Göttingen. There I learned techniques of electron microscopy from Simon Levay, who coincidently went on to work with Hubel and Wiesel at Harvard. At the time I was too naive to appreciate my good fortune, to have been delivered into the care of such a humane and capable mentor. During my five-month stay in Germany I was also introduced, while visiting the Max Planck Institute for Biological Cybernetics in Tübingen, to the power of a multidisciplinary team for analyzing a small nervous system -- in this case the optomotor systems of the housefly.

Returning to UCSD, I sought a lab where I might apply the histological skills I had acquired at Purdue and in Göttingen. Prof. Allen Selverston's lab provided a propitious niche: Selverston's research focused on the neural circuit properties of individually identifiable nerve cells in the lobster stomatogastric ganglion, but anatomical details of those cells remained relatively unknown. I began filling that gap, describing those cells by examining serial thin sections with electron microscopy.

In spite of my early impression at Purdue that I did not care for histology, I continued honing my skills in that technology. Those skills sustained my research into fly anatomy, both as a postdoc in Robert Wyman's neurogenetics lab at Yale and later as a zoology professor at SIUC. I had found an approach to histology -- serial sections of very small specimens embedded in plastic -- that suited me remarkably well.

Throughout graduate school and postdoctoral research, my histological experience had been limited to examining invertebrate tissue. I had never taken a course in histology, nor had I studied any human anatomy or physiology beyond the nervous system. Nevertheless, in 1978 I was hired by SIUC School of Medicine to teach human histology to first-year medical students. My first couple years at SIUC were therefore quite effortful, acquiring enough knowledge and building a sufficient collection of micrographs to sustain that teaching assignment. Twenty years later that image collection supported creation of a very popular internet histology resource to help students learn this discipline.

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Genetics

Throughout the 1970s I had been much too busy becoming a "neurohistologist" to keep up with developments in the rapidly expanding field of molecular genetics. Even while working in a Drosophila neurogenetics laboratory at Yale, I concentrated nearly all my attention not on the genetics of those flies but on their microscopic anatomy. Before I could write effectively about the evolutionary significance of repetitive DNA, during the 1990s and 2000s, I had a lot of catching up to do. Nevertheless, a seed for my eventual engagement with evolutionary genetics had already been planted during my senior year at Purdue.

The genetics course in Purdue's core biology curriculum was taught by a gifted pedagogue, Professor Edward H. Simon. In addition to scientific work, Simon published The Challenge of Genetics, a book of Problems Designed to Enlighten and Stimulate Students of Genetics. In his lectures, to avoid distracting students with too many complex details of real organisms, Simon adopted "schmoos" (image at right) as his favorite examples. Schmoos had been famously invented by cartoonist Al Capp, for his comic strip Li'l Abner. These marvellous creatures were able to turn themselves into anything that any other character wished for. Simon's schmoos could be imbued with whatever traits would best illustrate any particular aspect of genetics. (At the end of each term, Simon would award his highest-scoring student with an autographed print of schmoos.)

During his final lecture of the semester, one whose content would not be included in his final exam, Professor Simon presented a surprising case for the impossibility of evolution. He argued -- using estimates for the maximum numbers of organisms, cells, and DNA molecules that could ever have existed -- that the full span of geological time was far too brief for the evolution of all the different protein molecules now extant. I was puzzled, and a bit shocked. Why had Simon chosen to share this argument, especially during a period when the teaching of evolution was under intense political attack by religious fundamentalists? Could he, I wondered, have been challenging his students to find a flaw in his argument? Might there be some principle of genetics which could overcome the paradox he had presented?

Nearly thirty years later, while revisiting my alma mater in 1998, I stopped by Prof. Simon's office to say hello and to proudly show him the Trends in Genetics article that I had just published with Morris (Moshe) Soller. "Moshe!" he exclaimed, "He's an old friend of mine." Small world. But during our brief conversation I learned that Simon was himself a religious fundamentalist (albeit Jewish rather than Christian; he always wore a yarmulke to class). He really did NOT believe in an entirely mechanistic process of evolution. He had been prudent enough not to question evolution during regular class time, and wise enough not to base his anti-evolution argument on anything but science. Whatever his intent had been three decades before, my imagined interpretation of his long-ago lecture -- that something of significance might be missing from evolutionary theory -- had simmered for a decade before boiling over into my appreciation for "metaptation."

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Evolution

Not until after graduate school did I begin to embrace "evolution" as an area of special academic interest. Of course, evolutionary ideas had always permeated my natural history reading. Loren Eiseley's books The Immense Journey and Darwin's Century had especially impressed me, but Purdue's core biology curriculum had not included a course focused on evolutionary principles. (Neither did SIUC's Zoology Department have an evolution course until I introduced one myself.) I was finally drawn irresistably toward evolution by Steven Jay Gould's essays in Natural History magazine. Through such reading I gradually realized that adding a comparative, phylogenetic approach to my Drosophila research might open up a niche with less competition than mainstream neurobiology. And without Gould's personal encouragement, in his response when I sent him a fan letter, I might have lacked confidence to pursue further work in evolutionary theory.

With that shift in focus, my style of research began a transformation from simply describing individually differentiated nerve cells to exploring how such nerve cells might evolve. What attributes of biological organization might facilitate the evolutionary malleability of animal behavior? Thus was born the concept of "metaptation," followed by the obvious question: How might metaptation be implemented by genetics? That question led to imagining "evolutionary tuning knobs" based on repetitive DNA. Once such genetic tuning knobs turned out to exist in the real world of molecular genetics, I began to realize that the grammar of the genome might be parsed into more than just "genes" and "junk," to include a variety of "mutational protocols."
If "negative inspiration" can be a thing, my lack of formal education in evolutionary biology might have been essential for my subsequent development. By "virtue" of this deficit, I had inadvertently avoided becoming indoctrinated into the deeply-entrenched belief that natural selection must necessarily minimize mutation rates. I learned how severely this belief had distorted the field of evolutionary genetics only after I had acquired the intellectual tools to dismantle it. The evident reality of genetic tuning knobs encouraged me to continue challenging dogmatic understanding of mutation, in publications and presentations throughout the final decade my active career, a career which had finally acquired an enduring direction.

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History and philosophy

They say that aging scientists commonly turn to history or philosophy.

Many of the biology textbooks which I studied over the years included brief historical notes about the founders of the discipline. These were typically hagiographic, emphasizing what those pioneers had discovered, not how they might have erred. More substantial engagement with the history of ideas in biology, particularly in evolutionary biology, came with reading Loren Eiseley and Steven Jay Gould. From Eiseley I learned that the products of evolutionary adaptation elude simplistic understanding. From Gould I learned the limits of strict adaptationism. Gould's writing also taught me that challenging orthodoxy can bring hazard as well as potential reward: Appreciation from colleagues might not follow, even if one's heretical ideas are supported by nature.

As my retirement approached, I introduced a seminar/discussion course on the history of ideas in biology, hoping to engage students with the epistemology underlying reliable scientific knowledge. For one of my last publications (in 2012), I very intentionally collected historical examples, gleaned from several of the leading lights of evolutionary genetics, to illustrate how faulty epistemology had warped our current understanding of mutation.

But I was growing tired, without much mental stamina for engaging with professional literature. When I officially retired in 2014, I didn't yet know that my heart's output had become severely compromised. Time passed. In 2019 a surgeon replaced my aortic valve with tissue cunningly crafted from bovine pericardium. More time passed. I amused myself by resurrecting my histology website and by writing notes on the history of histology. Then, in 2023, I received a surprise invitation to write for a special "physiology of evolution" issue of The Journal of Physiology. I expect that essay, which reprises the "metaptation" theme from 1985 and 2010, will be my "swan song."

* * * * * * *

Nature study remains my abiding interest. I still occasionally discover a phenomenon which I had somehow previously overlooked, such as "frost flowers" extruded on a frigid morning from the desiccated stem of last summer's dittany. Or a pastel pink band (the "belt of Venus") bordered by deep blue in the western sky at sunrise, which I only recently understood to be the edge of Earth's shadow.

And of course I remain fascinated by insects.
(This flying fuzzball with a beak appears to be Bombylius major.)

The Road goes ever on and on
Out from the door where it began.
Now far ahead the Road has gone,
Let others follow it who can!

poem by Bilbo Baggins
The Return of the King
J.R.R. Tolkien