The network presented in iHOP currently contains 28.4 million sentences and 110,000 genes from over 2,700 organisms, including Homo sapiens, Mus musculus, Drosophila melanogaster, Caenorhabditis elegans, Danio rerio, Arabidopsis thaliana, Saccharomyces cerevisiae and Escherichia coli.
Example organisms used for high-content screening include the fruit fly (Drosophila melanogaster), zebrafish (Danio rerio) and mice (Mus musculus).