Representation of the skeleton in vertebrate anatomy ontologies.

<p>The vertebrate skeleton can be partitioned according to many different criteria – and it had been by the different groups (<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0051070#pone-0051070-t001" target="_blank">Table 1</a>) that developed anatomy ontologies. For example (<b>A</b>), ‘bone’ had been treated as a type of tissue by all except the MA, who also related it to the concept of ‘bone organ’. In the VSAO (<b>B</b>), the concepts of bone tissue and bone element were disentangled, named and defined. Individual bone elements were related to their tissue and cell components as well as developmental processes. From these links one can reason that, e.g., the ‘femur’ is <i>part_of</i> ‘endoskeleton’, <i>develops_from</i> ‘cartilage element’, and <i>participates_in</i> the process of ‘endochondral ossification’, whereas the ‘frontal bone’ is <i>part_of</i> ‘dermal skeleton’ and <i>participates_in</i> the process of ‘direct ossification’. Image on left shows chondrocytes embedded in a bone matrix developed from periosteum of fractured chick dermal bone. Image on right shows a late gestational stage mouse embryo stained with alcian blue and alizarin red. CL term is shown in yellow fill, tissue terms in grey fill, skeletal element terms in blue fill, and skeletal subdivision terms in green fill. Parent classes from CARO are in red font, GO terms in green font, TAO terms in blue font, and VSAO terms in black font.