Nephrologists sans frontières: on the metamorphosis of turning into a fly geneticist

Abstract

Going abroad for a postdoc to dedicate two or more years entirely to research is considered rather normal for a research-oriented nephrologist or internist. Going abroad for a postdoc in a fly lab is not considered normal. I saw the puzzled faces of people whom I had just told about my plans, and I heard warnings like "Working with flies is so far away from human disease!" or "The fly is not even a vertebrate!" I felt that these people were right, but that I still had to do it. Once I plunged into the fly world I found that there are even more reasons why working with flies seemed like a tough option for a nephrologist. Sitting every morning, for example, in the chilly and smelly fly room to examine and sort thousands of little bugs often makes me wonder why on earth I am doing this. As if it weren't annoying enough that they populate your garbage cans at home. Also, the habit of flies to eclose early in the morning regardless of the day is annoying. But these things can be tolerated by an MD. In fact, you get used to the routine business of fly work rather quickly, even to the early Sunday morning stroll to the lab to pick virgin flies. Other drawbacks are more challenging, such as the inaccessibility of Drosophila biology and genetics to newcomers. Especially to intruders from the medical field, the Drosophila world appears to be full of mysteries. Without background knowledge gained in zoology classes, the nomenclature of Drosophila anatomy is hard to grasp in the beginning. Equally difficult is the nomenclature of Drosophila genetics. C(l)RM,y2/Y;ln(2LR)),Cy/Sco;cid/eyd, for example, is, so I learned, a rather simple genotype. The high art of recognizing markers is like trying to understand a completely incomprehensible foreign language. Markers are used to mark the chromosome or the chromosome arm you are trying to follow or to lose in a genetic crossing scheme. Marker mutations are the key to deciphering genotypes, and they are the reason why Drosophila genetics is so special and powerful. Markers allow genotyping just by simply looking at the flies, rather than analyzing DNA. The information can be hidden in the eye color, eye shape, wing shape, wing vein morphology, bristle color, bristle shape, and so on. However, you have to know what you are looking for. If you cannot see the markers you are not a Drosophila geneticist. Descriptions of the marker phenotypes can be found in Lindsley and Zimm, a several-hundred-page reference book and the bible of every Drosophila researcher.1 But for the frustrated wanna-be fly geneticist it is probably more advisable to kindly ask a patient colleague who already has become a member of the holy fly geneticists' circle to share some of his or her wisdom. If you try to decipher the coded language of Lindsley and Zimm, you might get the impression that the high art of Drosophila genetics is kept as the secret of the 'chosen ones' only in order to keep out undedicated researchers and medical doctors.