Two days after her Mount Holyoke graduation, April Dinwiddie was presenting her research at an international conference titled IEDG 2008: Integrating Evolution, Development, and Genomics at the University of California at Berkeley. Her poster, “In the Blink of a Wing,” was one of three posters to win the conference prize, determined by a vote of all the attendees. Fifty-three of the posters were the work of graduate students, postdocs, or professors. Dinwiddie, a biology major, was one of two undergraduates presenting posters.
Dinwiddie’s research on an extinct biting midge had already garnered recognition before she’d left South Hadley. First, Dinwiddie, who grew up in Palo Alto, California, won the Kathryn Stein Prize for Best Thesis in Biological Sciences. Then, she was one of two students to win the Phi Beta Kappa Prize for outstanding work by a senior at Mount Holyoke. Margaret Massey ’08, the other winner, and Dinwiddie were the speakers at the Phi Beta Kappa Initiation during Commencement Weekend.
“It was my first scientific meeting,” Dinwiddie recounted. “The different approaches in the field were striking, and I knew where I would want to fit. Very talented MHC alums were all around, and they were very encouraging and supportive. I enjoyed sharing this fossil with experts in developmental biology. My work was different from theirs, but they saw the connection.”
As thesis advisor and professor of biology Stan Rachootin notes, Dinwiddie “got to evolution late in her biology major – as a second semester admit, she was a year behind the rest of the biology students in her class, but she made up for lost time. When a single fossil in an evolution lab stopped her in her tracks – a tiny extinct biting midge in transparent amber – it was clear that she would pursue it as a thesis. Each wing carried an organ that looked like a compound eye. Dinwiddie spent last summer studying this fossil, thanks to the Howard Hughes PROGRAM AT Mount Holyoke. She discovered previously unidentified specimens at the museum of Comparative Zoology at Harvard. Then she proceeded to teach herself paleontology, entomology, biomechanics, and molecular developmental biology.”
Investigating the Extinct Midge
Dinwiddie started with the published suggestion that the wing organ was used for making sound – “stridulation” – much like a cricket’s system of sound production. She modeled ways in which the wing organs might have been used as musical instruments, and found that one was physically possible. Then she calculated, with the help of physics professor Mark Peterson, the frequency of sound that would be produced. It was far higher than any sound produced by an insect. She went on to show that communication by light reflection off of the wing organs made a much better case, one that fit with the senses and the activities of living midges.
Dinwiddie obtained the first scanning electron microscope images of the wing organ, and these revealed a new feature that it shared with the surface of the fly’s compound eye. She compared the genes that are expressed in the wings and eyes of the living fruit fly to map the wing organ’s development in the extinct midge. Dinwiddie concluded that a sector of the developing wing had captured the outer surface of the fly eye.
Rachootin noted, ‘Evolutionary developmental biology has demonstrated deep, surprising congruencies in the basic design of bodies, between, for instance, flies and us. April looked through the other end of the telescope – she found a striking change in the last stage of development, a swap between two pathways that manage to stay separate in the million living species of flies. April gave me a great reason to reverse the conclusion of my lectures on Evo-Devo this year.”
The Conference and Beyond
At the Berkeley conference, Dinwiddie found herself in a world where Mount Holyoke is well known. Two of the conference organizers, alumnae MONIKA Abedin ’03 and Mansi Srivastatava ’03, have recently published papers that bear directly on evolution, development, and genomics. The work of newly minted Berkeley Ph.D. Deirdre Lyons ’02 was presented at the symposium. This has been a really incredible experience.”