You might be wondering how I could possibly write another post about tomatoes this year, but what can I say? They don't call me
Solanaceae for nothing-- I just love these plants! Sam and I picked these still-green tomatoes at dusk the other day, anticipating a killing frost that night. Sure enough, by this morning most of our garden finally looked like winter, and we'll be happily ripening these babies indoors and digging up some green tomato recipes. If all else fails, at least we had fun picking tomatoes one last time.
Taking these pictures I was reminded of my year in graduate school, just before Sam was born, working towards a Masters of Science in Botany. As an undergraduate I did not take a single hard science class, so to qualify for my program I took over a year's worth of Biology and Chemistry courses, including, I am proud to say, the dreaded Organic Chemistry. Once I was a grad student, I was really turned on by Evolutionary Botany, and chose a thesis project that my advisor had already started and funded. We were to determine the phylogeny, basically the genetically-based family history, of a couple dozen species of closely related plants from tropical areas around the world. I spent hours and hours in a lab extracting and analyzing strings of DNA from plant material that other research partners had collected.
I was also taking a course with my advisor titled Species and Speciation, which explored the many concepts and studies concerning the definition of a species and how different species arise from common ancestors. I loved this class because it was basically a philosophy of life class, in the language of biology and evolution. As a final paper, we had to design a research project and write a project proposal exploring something about how species become species.
To get technical for just a moment, the classic definition of a species states that accumulated genetic changes in geographically segregated populations driven by advantageous adaptations to new environments can have the effect of reproductive incompatibility and isolation, thus generating new species. (I lifted that sentence straight from the paper I wrote 4 years ago.) Basically what that means is that a population of organisms migrates and encounters some kind of geographical barrier, like a mountain range or an island, with some of the population going one way and others going the other way. Over time, each group adapts to their new and different environment, causing an overall genetic change. Once these groups have diverged genetically from each other, they can no longer mate, which defines them now (many many many generations later) as different species. Fascinating, isn't it?
Which brings me back to tomatoes, because for the final assignment I designed a project looking at two species from the Solanaceae family, relatives of our beloved tomato. Earlier in the semester I had read a tiny reference about these plants from some obscure dissertation, and I was fascinated. I am quite sure that my fascination was at least partially due to the fact that these were Solanum species; however, to me they also were great potential study subjects because of a particularly controversial phenomenon within speciation called character displacement. I'd love to write about it but I'm sure nobody is reading anymore anyway, so I'll just finish this up by saying that I wrote that paper with more passion than I ever felt for my actual research project. My professor loved it and told me that I had gone above and beyond the scope of the assignment, basically writing a proposal worthy of Ph.D. research.
As most of you know, I never ended up finishing my graduate program. Marriage, a job offer, a rough pregnancy, and wanting to return to California all drove me to leave my research and my advisor and not look back. If I ever do try again for a Masters in Botany, I won't sign up for years of research with plants that don't fascinate me. I won't be studying anything that somebody else decided was important. I will study something awesome and interesting and relevant to me, something like tomatoes. Or their very cool relatives.
