Gene Ontology (GO) is a useful resource of controlled vocabulary that provides information about annotated genes. Based on such resource, finding the biological function is useful for biologists to come up with different hypotheses and help further investigations of an experiment. The biological function for desired genes and gene associations is picked up from a randomly chosen list or through the analysis of differential gene expression. Many tools have been developed to utilize GO knowledge and cluster genes according to relevant biological functions. The retrieved GO terms include both specific and non-specific terms, which is not user-friendly in terms of data analysis. Thus one approach is still missing, which allows navigating through different levels of GO hierarchy manually. We developed a tool, GOTrapper, which allows moving up or down to the very bottom of the GO hierarchy. This is performed manually by the user, based on an assigned threshold. This tool grabs the shared terms by the desired set of input genes of Homo sapiens. Here, two inputs are possible. “Within” is to find associated terms within one gene list, and “Between” is to find associated terms between two lists. The tool also provides the option to return the terms with the pre-selected evidence codes. GOTrapper is a user-friendly Java tool that helps the user move up and down the ontology tree, which leads to new hypotheses and devising new association of the input genes. It also allows returning terms of associated genes based on selected evidence codes. This tool can be accessed and is freely available at https://github.com/BioGeneTools/GOTrapper .

Reanalyzing a large methylome dataset of 225 schizophrenic and 450 control samples derived from the prefrontal cortex revealed that 6 male patients have predominantly hypomethylated probes mostly on chromosome X, affecting the same genes in all six. Network analysis of the differentially methylated genes revealed a dense network of transcription factors, histone and chromatin remodeling proteins, with 15 of the X-located genes expressed at the synapse, including NLGN4X , SYN1 and MECP2. Mapping a recent experimental dataset of G-quadruplexes (G4s) onto the differentially methylated probes revealed that the probes in the group of six overlapping with G4s on chromosome X are significantly more hypomethylated than non-overlapping and non-X probes whereas in the rest of the patients G4-overlapping probes are more methylated than non-overlapping ones, revealing a distinct pathology, involving chromatin remodeling for the six patients. Unexpectedly, the hypomethylated genes in them significantly overlapped with gene locations where X-inactivation escapism was observed in women.