Comprehensive analysis of pseudogene expression in human and macaque brains compared with other tissues

Although gene expression in the brain has been extensively investigated and compared to other tissues, the activity of pseudogenes has not been comprehensively surveyed. Here, leveraging large-scale RNA-seq data, we construct consistent pseudogene expression profiles in human and macaque brains and compare them to 29 other tissues. We further annotate pseudogenes with potential cellular roles based on co-clustering them with protein-coding genes. Notably, the majority of the expressed pseudogenes show elevated expression in the brain relative to other tissues, and these pseudogenes show broad and consistent expression patterns across brain subregions. Furthermore, spatiotemporal analyses reveal that pseudogenes in different brain subregions have greatly varying temporal trajectories (e.g., increasing vs. decreasing), in contrast to protein-coding genes that tend to be more uniform. Finally, we identify a set of pseudogenes exhibiting significant changes in neuropsychiatric disorders, some of which overlap with known brain eGenes (genes whose expression is associated with expression quantitative trait loci, eQTLs), as well as with genes implicated by genome-wide association studies (GWAS). Together, our study provides a public resource of pseudogene expression in human and macaque brains (in comparison to other tissues) and highlights aspects of pseudogene expression in brain development and pathogenesis.