The fruit fly, Drosophila melanogaster has become a leading organism in studies of development because of the availability of mutants which influence development. These mutations have served as “Rosetta Stones” in the deciphering of the mechanisms and pathways by which genes control development.
At The Exploratorium, a site hosted by the San Francisco Museum system, you can view pictures of naturally occurring fly mutants. Many of these have an effect on development. For example, the eyeless gene encodes the transcription factor Pax6 (Box 5E Wolpert text); the antennapedia gene encodes a transcription factor with a homeodomain (Box 5E Wolpert text).
Some of the developmental mutants in Drosophila are embryonic lethal, which means that the flies die as embryos due to severe developmental defects. The maternal gene bicoidand the zygotic gene fushi tarazu (ftz) are such genes. To see the effects of these mutations on development, go to: http://flybase.org/data/images/Animation/embryogenesis.mpg
Follow “Image Browser” links to the animations. Watch the animation called "embryogenesis.mpg". Notice the place at the posterior end (right side of screen) where the pole cells will migrate to the interior. Also count the segments visible at the end of embryogenesis. Now view the movies called "bcd-gastrulation" and ftz-gastrulation" (http://flybase.org/data/images/Animation/). Review the role of these genes in embryogenesis (bcd and ftz on p. 47 of Wolpert text). Based on this phenotype, how do you think bicoid (which is a form of "bi-caudal") and ftz (which is Japanese for "too few segments") got their names?
FlyMove is a library of animations that facilitate the understanding of complex developmental processes in Drosophila melanogaster. Learn how the classic screens for segmentation defects were performed by following the links under “Processes” and “Segmentation”, and then download the animations.
The study of Drosophila development has led to remarkable progress in the molecular understanding of mammalian embryology. The Interactive Fly, created by Thomas Brody and hosted by the Society for Developmental Biology is a great guide to resources related to fly development. Follow the links under “Study Aids” to “Developmental Pathways” and choose an evolutionarily conserved developmental pathway like “Activin signaling pathway” to learn more about the relationship between homologous genes that drive imaginal disc formation in the fly (pp. 41-42 in Wolpert text) and are involved in colorectal and lung cancer in mammals.
Only 11 science Nobel Prize winners are women, and one of them is developmental biologist Christiane Nüsslein-Volhard. Look up the 1995 award, shared with Edward B. Lewis and Eric F. Wieschaus for their work on the genetic control of the early embryo. Review video interviews and biographies for each biologist. How did winning the Nobel Prize impact Nüsslein-Volhards career, and how has she worked to encourage female scientists?