Description
Since the beginnings of evolutionary biology the descent of birds from theropod dinosaurs has been a hot topic. Two key elements of this discussion are the homology of avian and dromeosaurian digits and how developmental biology can inform studies of digit homology and limb evolution. This study aims to add new micromorphological data to the debate using high resolution 3D images made with x-ray microCT, which has recently become a powerful tool in embryology. In the past the usefulness of microCT in this field has been limited because of the low contrast of embryonic tissue. But recently simple staining methods have grown available that allow such an intent. Fore and hind limbs of the model organism Gallus gallus were examined at stages which previous studies have shown are of importance to this topic (Hamburger-Hamilton stages 26-31). Two contrast stains, PTA (tungsten) staining after Bouins fixation and I2E (iodine) after formalin fixation, are tested and compared. Our results are discussed with a view to the classical morphological, histological, and paleontological pictures of birds' fore limbs and their development, as well as to images from expression studies of genes from the Sox and Hox families. Preliminary results suggests that the methods used will be useful, since a fourth fore limb digit-anlage was clearly visible at stage 31. We conclude that microCT can add helpful new embryological data to this long-standing problem in developmental evolutionary biology.| Period | 2010 |
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| Event title | Nicht angegeben |
| Event type | Other |
| Location | UnknownShow on map |