Then from this graph the closest MeSH terms are selected. Other concepts than the SC itself can be used to start populating the graph of ancestors. In the event of using concepts other than the SC itself as the seed for the graph, the concepts chosen as the seed must be compatible in semantic type assignment. Siblings of the SC must have at least one ST in common to be used as seed of the graph. MeSH terms are double framed.
Arrows point to parents or broader concepts.
Building the graph of the ancestors of the SC . The ancestors of a given concept can be represented as a directed graph, ideally acyclic. Starting from the seed, its parents and broader concepts are added to the graph. Then, recursively, parents and broader concepts of all newly added concepts are added, until no new concept can be found. To prevent non relevant concepts from being added to the graph, the semantic types of any concept added to the graph must be compatible with those of its direct descendant in the graph.