Glass, Arthur W.

Hamrum, Charles L.

Sisson, Vern

English

University of Minnesota, Morris (UMM): Digital Well

Journal of the Minnesota Academy of Science Volume 30 Number 1 Article 7 1962 The Apparent Genetic Relationship Between Campaniform and Trichoid Sensilla on Drosophila Wings Vern Sisson Gustavus Adolphus College Charles L. Hamrum Gustavus Adolphus College Arthur W. Glass Gustavus Adolphus College Follow this and additional works at: https://digitalcommons.morris.umn.edu/jmas  Part of the Zoology Commons Recommended Citation Sisson, V., Hamrum, C. L., & Glass, A. W. (1962). The Apparent Genetic Relationship Between Campaniform and Trichoid Sensilla on Drosophila Wings. Journal of the Minnesota Academy of Science, Vol. 30 No.1, 25-26. Retrieved from https://digitalcommons.morris.umn.edu/jmas/vol30/iss1/7 This Article is brought to you for free and open access by the Journals at University of Minnesota Morris Digital Well. It has been accepted for inclusion in Journal of the Minnesota Academy of Science by an authorized editor of University of Minnesota Morris Digital Well. For more information, please contact skulann@morris.umn.edu. the Great Lakes Region. Bloomfield Hills, Michigan, Cranbrook Institute of Science. LAGLER, KARL F. and HARRY VAN METER, (October, 1951), Abundance and Growth of Gizzard Shad, Dor-osoma cepedianum (Lesueur), in a Small Illinois Lake, The Journal of Wildlife Management, XV:357-60. LEWONTIN, RICHARD C., ANNE RosE, and GEORGE G. SIMPSON. 1960. Quantitative Zoology. New York, Harcourt and Brace. MAYHEW, JAMES. (January, February, March, 1958), Notes on the Observations of the Reproductive Habits of the Gizzard Shad in Two Iowa Lakes, Iowa Quar-terly Biology Reports, XIII: 157-76. STROUD, RICHARD H. (April, 1949), Growth of Norris Reservoir Walleye During the First Twelve Years of Impoundment, The Journal of Wildlife Management, XIII: 157-76. SWINGLE, H. S. (1946), Experiments with Combinations of Largemouth Black Bass, Bluefills, and Minnows in Ponds, Transactions of the American Fisheries Society, LXXIV: 46-62. TRAUTMAN, MILTON B. 1956. The Fishes of Ohio. New York: Macmillan Co. ZOOLOGY The Apparent Genetic Relationship Between Campaniform and T richoid Sensilla on Drosophila Wings. 1 VERN SISSON, CHARLES L. HAMRUM, and ARTHUR W. GLASS Gustavus Adolphus College, St. Peter, Minnesota During campaniform sensilla experiments in 1960-61, the authors encountered a wing bristle abnormality in the F2 and F3 individuals from white eye x curved wing crosses. These structures either appeared as normal tri-choid sensilla in a location normally occupied by cam-paniform sensilla, or as intermediate structures between the trichoid and campaniform sensilla. Also, additional trichoid sensilla were added on veins not previously oc-cupied by either campaniform or trichoid sensilla. Lees ( 1941) also described such intermediate structures on the veins of the "hairy" wing mutant of D. melanogaster. Lees found the "hairy" wing mutant to have almost twice the normal number of campaniform sensilla. These find-ings prompted Lees to suggest that the trichoid and cam-paniform sensilla are homologous structures. The derivation of the various types of insect sensilla from a single basic type has been previously suggested. Snodgrass (1935) hinted that campaniform sensilla may have lost the bristle with the sockets alone remaining. Waddington (1956), and Lees and Waddington (1942) stated that the basic trichogen cell position was altered in relation to the tormogen cell position by the various genetic effects to produce the bristle mutaH9ns. The authors' (1961) investigations support Lees' idea on the homology of the campaniform organs. Continued work in this area has been even more indicative of this hom-ology. METHODS: The authors developed a procedure which makes it possible to observe the distribution of wing sensilla without sacrificing prospective parents. This was done by isolating Drosophila pupae and allowing them 1 Supported by National Science Foundation Undergraduate Research Participation Grant. Proceedings, Volume Thirty, No. One, 1962 to emerge. As soon as the wings had opened, the l~ft wing was cut off just beyond the axillary sclerites. The tool used for cutting was a razor blade chip mounted in a handle. A fine tweezers was used to hold the wing dur-ing the amputation. The wing was then boiled one min-ute in 95% alcohol, cleared in xylene, and mounted in Piccolyte on a slide, using a coverslip over it. REsUL Ts: The curved wing mutant was used for the original parental stock. The experiment originally called for selective matings to produce a high-number cam-paniform line and a corresponding low line. In both high and low lines, extra campaniform sensilla were observed on the R1 wing area. However, the high-line displayed a trichoid sensilla quite consistently on R1, while the low-line displayed it approximately one half of the time. None of the high or low line parents used in these crosses showed these structures; however, a few other curved wing flies from the parental stock had a small number of tricp.ia. The trichoid-displaying flies were then inbred. Once again, as had been encountered in previous years, the trichoid sensilla and intermediate structures were found occupying locations where campaniform organs previously were found. In the absence of a trichoid sen-sillum, a campaniform organ would again be found at that location. The trichoid sensilla were found to occupy quite predictable positions. In this line, as had been the case in the past, trichoid sensilla did not appear until additional campaniform organs were added, particularly on the R 1 wing area. Figure 1 shows a comparison of the wing of a "tri-choid" fly with the wing of a normal wild type fly. At-tention should be directed to those areas which are de-noted as being predictable sites for trichoid sensilla. 25 F 2 generation, a recurrence of extra campaniform sen-silla was observed in some cases. Macdowell (1915), who worked with extra bristle inheritance on the thorax of D. ampulae, found that the F 2 generation exhibited an A Cu R4/5 approximate 3 · 3: 1 ratio of normal to extra bristles. This led him to suggest a simple Mendelian inheritance. The ratio of normal to extra campaniform sensilla in the F2's in this study was somewhat similar to that of Macdowell. The ratio was 26 normal to 5 extra campaniform sensilla which, when tested with a Chi-square against a 3: 1 ratio gave a value of 1.314. This would mean that the vari-ation from the 3 : 1 hypothetical ratio would be explained 30% of the time by chance alone; well above the 5 % critical level. B FIGURE I: A comparison of normal wild type fly wing (A) show-ing campaniform sensilla locations with a hypothetical wing of the "trichoid" type (B) showing all predictable campani-form and trichoid sensilla locations. Table 1 represents a comparison of wild stock, the parent curved wing stock, and the "trichoid" line. TABLE I. Comparison of the sensilla populations of the wild, curved, and "trichoid" stocks. R, &,, R,,, C" Wild campaniform 3 0 4 0 trichoid 0 0 0 0 Curved campaniform 3-6 0 4 0 trichoid 0 0-1 0-2 0 "Trichoid" campaniform 4-7 0-1 4-6 0-2 trichoid 0-2 0-2 0-3 0-5 Figure 2 represents an enlargement of certain areas of a wing vein showing the various types of sensilla. ~ a r C FIGURE II: Sensilla types found on Drosophila wings. a. trichoid, b. intermediate, c. campaniform. An outcross of the "trichoid" line was made by mating it with the normal wild type fly. All Fi's examined ex-hibited the normal campaniform distribution of the wild type, and no trichoid sensilla were observed. Among the 26 SUMMARY AND CONCLUSIONS: Because of the inter-changeability of campaniform and trichoid sensilla, it seems quite apparent that the two organs are closely related. The appearance of intermediate structures would seem to make this even more conclusive. Because the appearance of the Fi's and F/s of the outcross approximated that of Macdowell, it seems logi-cal to suspect the same inheritance mechanism, i.e., monohybrid-complete dominance. Since an increase in campaniform organs seems necessary before trichia ap-pear, the same trigger mechanism apparently allows the production of both. This trigger mechanism seems to re-move an inhibitor of some sort which previously held the sensilla population to that of the normal wild type. When this inhibitor was removed (through selective mat-ings and inbreeding) additional factors seem to be in-volved in penetrance and/or expressivity. This would account for the variability in the number of trichoid sen-silla in the "trichoid" line flies. What these factors are remains unknown. The writers gratefully acknowledge the technical aid of Karen Hawkinson and Richard Lindquist in the com-pletion of this study. LITERATURE CITED HAMRUM, C. L., A. w. GLASS and V. SISSON. 1961. Campaniform Sensilla Patterns on the Wings of Droso-phila. Proc. Minn. Acad. Sci. Vol. 29: 240-44. LEES, A. D. 1941. Homology of the Campaniform Or-gans on the Wings of Drosophila melanogaster. Nature (London). 150: 375. LEES, A. D., and C. H. WADDINGTON. 1942. Develop-ment of the Bristles in Normal and some Mutant Types of Drosophila melanogaster. Proc. Royal Soc. London, B, 131: 87-110. MACDOWELL, E. C. 1915. Bristle Inheritance in Droso-phila. Jrn. Exp. Zoo[. 19: 61-98. SNODGRASS, R. E. 1935. Principles of Insect Morphology. New York, McGraw-Hill Book Co. WADDINGTON, C. H. 1956. Principles of Embryology. New York, Macmillan Co. The Minnesota Academy of Science 

The Apparent Genetic Relationship Between Campaniform and Trichoid Sensilla on Drosophila Wings

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The Apparent Genetic Relationship Between Campaniform and Trichoid Sensilla on Drosophila Wings

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