Keyword co-occurrence networks.

<p>(A) Keyword co-occurrence network containing only nodes with degree ≥ 10. Nodes represent keywords, and edges denote the joint appearance of keywords in a publication. Only nodes with degree ≥ 10 are shown. Both nodes and edges are scaled proportionally based on Bezier curve. Nodes are colored based on their categories: genotype, phenotype, analysis, and others. (B) Temporal profiles of selected keywords show the normalized frequency (frequency of keywords divided by number of publications) from 2008 to 2014. Hierarchical plot indicates clustering of selected keywords.