T. H. Morgan, Nettie M. Stevens, and the Trouble with Aphids
| dc.contributor.advisor | Davis, Gregory K. (Biologist) | |
| dc.contributor.author | Johnson, Claire | |
| dc.date.accessioned | 2022-08-19T13:59:13Z | |
| dc.date.available | 2022-08-19T13:59:13Z | |
| dc.date.issued | 2022 | |
| dc.description.abstract | When one considers the greatest discoveries in the history of biology, one is naturally drawn to think of well-known model organisms, such as mice or Drosophila melanogaster, which have been the backbone for most contemporary discoveries. Yet, along the way, there have been many other organisms—marine and terrestrial—that have bolstered our understanding of genotype-by- environment interactions (called polyphenisms) and organismal development. Aphids are one of these organisms. Aphids are particularly interesting for their cyclically parthenogenetic lifecycle: phases of female-only asexual reproduction in spring and summer, and male and female sexual reproduction in winter. It appeared to many that the determination of sex was due to environmental factors such as temperature or nutritional supply. Thomas Hunt Morgan, Chair of Biology at Bryn Mawr College from 1891-1904, chose to study aphids and their close relatives because he thought they would provide evidence in his favor in a long-standing conflict regarding the chromosomal theory of sex determination to which he was opposed, instead believing that the cytoplasm was at the heart of heredity and development. In 1905, he encouraged his former Ph.D. student at Bryn Mawr, Nettie M. Stevens, to study aphid development—specifically, the production of males, asexual females, and sexual females. In 1906, Morgan studied the development of a close relative of aphids, phylloxerans. Both he and Stevens committed the same crucial oversight. What had been overlooked and how? The complex lifecycle and biology of aphids may be the culprit. In 1908 and 1909, respectively, Morgan and Stevens—prompted by the former—revisited their own previous works and corrected their oversights. The back-and-forth communication between Morgan and Stevens during their studies of phylloxerans and aphids, respectively, arguably primed Morgan to be able to accurately apply the concept of sex linkage to his discovery of the famous mutant, white-eyed fly. He came to accept the truth of the chromosomal theory of sex determination in Drosophila, the very theory he had vigorously opposed. | |
| dc.description.sponsorship | Bryn Mawr College. Department of Biology | |
| dc.identifier.uri | http://hdl.handle.net/10066/24646 | |
| dc.language.iso | eng | |
| dc.rights.access | Dark Archive until 2027-01-01, afterwards Tri-College users only. | |
| dc.rights.uri | http://creativecommons.org/licenses/by-nc/4.0/ | |
| dc.title | T. H. Morgan, Nettie M. Stevens, and the Trouble with Aphids | |
| dc.type | Thesis |