Comparative immune-relevant transcriptome reveals the evolutionary basis of complex traits.

Comparing transcriptome can help us reveal the genetic and evolutionary architecture underlying complex phenotypes within and between species. Here, by analyzing 386 publicly available RNA sequencing samples using a uniform bioinformatics pipeline, we systematically compared expression profiles of 10 immune-relevant tissues across humans, mice, pigs, cattle, sheep, and chickens. In general, we demonstrated that gene expression of orthologous genes was conserved within tissues across species. By integrating our findings with results of genome-wide association studies (GWAS) from 17 health-relevant traits in humans and 16,539 health-relevant quantitative trait loci (QTLs) in animals, we found that transcriptionally conserved genes were significantly enriched for more heritability of complex traits, compared to species-specific genes. In conclusion, our results advanced the knowledge of the transcriptome evolution of immune tissues and demonstrated that multi-species transcriptome comparison is highly informative for understanding the genetics of complex traits/disease.