| Popis: |
Mammals exhibit a spectrum of morphological variation in their skeletons. Morphological variation in this project focuses on the vertebral column; within the vertebral column, the diverse patterns of intervertebral and epiphyseal fusion in mammals, with particular emphasis on extinct and extant cetaceans (whales, dolphins, and porpoises). Intervertebral fusion is present in some cetaceans between the cervical vertebrae in the neck, while terrestrial mammals fuse the sacral vertebrae. These two regions of intervertebral fusion, the sacrum of terrestrial mammals and the necks of some cetaceans are the only regions of the vertebral column to undergo fusion. To understand the mechanism behind intervertebral fusion and bone formation within the sacral intervertebral discs of terrestrial mammals and the cervical intervertebral discs of some cetaceans I investigate genes expressed during long bone endochondral ossification (MMP13, TIE2, ColX, and BMP2/4) as a model of intervertebral fusion. Other molecules pursued include ANK, a mineralization inhibitor and GDF5 and GDF6, which are present during joint maintenance. The patterns of protein expression exhibited in the mouse sacrum are compared to the whale cervical vertebrae to identify a mammalian module of intervertebral fusion. Epiphyseal fusion patterns are also investigated and compared between some terrestrial and aquatic extinct and extant mammals to determine if epiphyseal fusion patterns are consistent across mammals and if these two types of fusion present in the vertebral column are related. |
