28.3 Wednesday, Jan. 4 Conservation and function of noncoding RNAs in primate evolution BABBITT, C. C.*; PFEFFERLE, L. W.; FEDRIGO, O.; WRAY, G. A.; Duke University; Duke University; Duke University; Duke University firstname.lastname@example.org
Changes in the expression of genes play an important role in the evolution of phenotypes, however, protein-coding DNA is not the only DNA to be transcribed. Yet, it is currently unclear what fraction of noncoding transcripts are biologically relevant. Evolutionary conservation at the level of sequence, position, and expression is one approach for understanding transcript functionality. Here, we use directional paired-end RNA-Seq data to assess changes in global transcript abundance in five tissues of humans, chimpanzees, and rhesus macaques. We assay expression in noncoding intergenic regions, including both sense and antisense (relative to nearby genes) noncoding transcripts. We find that an abundance of noncoding transcripts, including many never previously annotated, are conserved in both location and expression level between species, suggesting a possible functional role for the broader category of conserved transcripts. We find a significant enrichment of intergenic RNA expression in regions flanking both the 5’ and 3’ regions of protein-coding genes. While the expression of noncoding RNAs are more conserved than expected by chance, expression levels can change rapidly over evolutionary time, with sense transcripts more conserved than antisense noncoding RNAs. We also find a negative correlation between 5’flanking antisense transcripts and the expression of the downstream gene, suggesting that these antisense transcripts are playing a regulatory, possibly repressive, role for nearby genes. Looking more broadly over multiple tissues, we find that many of these noncoding transcripts are playing tissue-specific roles. Comparative approaches may provide important insights into genes responsible for differences in metabolic functions between humans and non-human primates, as well as highlighting new candidate noncoding transcripts for further functional studies.