Thursday 30 May at 1pm
Thursday 27 June at 1pm
Dr Yoshiyuki Yamamoto
My research goal is to understand the molecular mechanisms underlying the generation of morphological novelties during evolution. I am currently using the Mexican characin Astyanax Mexicanus as a model system for studying micro- and macroevolution and development.
|Those pictures are from "Dr Axelrod's ATLAS of Freshwater Aquarium Fishes", Dr. Herbert R. Axelrod. TFH publications; 9th edithin (1997).|
Astyanax Mexicanus exhibits both eyed surface (surface fish: Figure 1) and eyeless cave (cavefish: figure 2) populations. I use molecular and experimental embryological techniques to study the developmental mechanisms by which this evolution occurred. Like zebrafish, this species provides an excellent system for studying embryonic development, but is especially useful for exploring the microevolution of developmental mechanisms. Cavefish have evolved regressive characters such as a degenerate eye, small optic tectum, and less pigment. They have also evolved constructive characters such as a large jaw and additional teeth, cranial neuromasts, and taste buds. This species allows straightforward investigation of the following evolutionary issues.
- Mechanisms and evolutionary forces of cavefish eye degeneration
- Cavefish brain evolution
- Craniofacial development and evolution in cavefish
Astyanax Mexicanus is a member of the order characiformes. However, Astyanax have a “generalized” body shape, the fish in this group have evolved a variety of unique characters. For example, piranhas have a blunt nose with razor-sharp interlocking teeth, neon tetras have beautiful patterns of pigments, pencilfish have an elongated body, and hatchetfish have a trenchant body with large pectoral fins (Figure 3). My research goal for macroevolution is to reveal the evolutionary developmental mechanisms of those unique characters by comparing their development to the typical tetra development of Astyanax Mexicanus.
If you are interested in participating in this research, feel free to contact Yamachyan, e-mail email@example.com
Page last modified on 14 oct 10 11:10 by Glenda Young