Gene Ontology and pathway enrichment analysis of differentially expressed genes

Gene Ontology (GO) is a major bioinformatics method for annotating genes and gene products identifying the characteristic biological properties of high-throughput genomic or transcriptome data, based on a rigorous biological background and adopting a unified database of structural annotation genes to standardize genes from molecular functions, biological processes, and cellular components, respectively [12, 13]. KEGG was used for pathway analysis of differentially expressed genes (DEGs) referring to the metabolic pathway, which is significantly changed under the known experimental conditions. Therefore, it is particularly important to study this underlying mechanism. We used DAVID (https://david.ncifcrf.gov/) to conduct a correlation analysis [14], to analyze the functional levels of DEGs, KEGG pathway, and GO enrichment, including GOTERM_MF_FAT, GOTERM_CC_FAT, and GOTERM_BP_FAT, which described the molecular function (MF), cellular component (CC), and biological process (BP) of the DEGs. In addition, test P < 0.05 was considered significant. All DEGs were uploaded to the online software DAVID to identify overrepresented GO categories and KEGG pathways.