rRNA paralogs with variations, rRNA-subtypes, affect diverse human phenotypes.

Eukaryotic ribosomal RNA (rRNA) genes exhibit hyper-variability at non-conserved regions known as Expansion Segments (ESs). Due to the numerous rRNA copies in the genome, editing ESs is challenging, and their significance remains unclear. In this study, we analyze rRNA variant frequencies in the UK Biobank population, revealing that highly abundant ES variations are causally linked to human health and physiology. We developed a Ribosome Variation Analysis (RiboVAn) method, identifying both heritable germline variants and a larger proportion of low-heritability, likely somatic variants. The most heritable variants cluster within four ESs of the 28S rRNA, with specific variants in es15l associated with adiposity, es39l linked to body dimensions, and es27l associated with blood-related traits and diseases. Variant-chromosome specificity is observed where functional variants are linked to certain rDNA chromosomes. These findings causally link rRNA sequence variation to human traits and establish that ESs have distinct and important functions in human physiology.