2022 Theses Doctoral

Common and rare genetic effects on the transcriptome and their contribution to human traits

Einson, Jonah

Bridging the gap between genetic variants and functional relevance is a principal goal of human genetics. Despite centuries of research, interpreting the biological mechanisms that link variants to phenotypes is a continuous challenge. This goal applies to rare and common variants, although the specific challenges vary depending on the variant’s frequency and effect on gene dosage or protein structure. Deciphering these variants’ modes of action is crucial for a more holistic understanding of genome regulation.

This dissertation advances interpretation of rare and common variants across the annotation spectrum, by utilizing functional data derived from population scale RNA-sequencing studies. Thus, three main research questions are addressed: (1) How do rare variants affect gene expression, and can these subtle changes be robustly detected? (2) How do common variants that influence pre-mRNA splicing influence protein structure and human traits? (3) Can joint effects between common splice-regulatory and rare loss-of-function variants be detected through the lens of purifying selection? All three chapters build on knowledge acquired through large-scale transcriptomics and open access data.

Chapter 1 evaluates the utility of allele specific expression to prioritize variants with functional effects. Chapter 2 involves quantifying splicing using the common Percent Spliced In (PSI) metric, and performing quantitative trait locus (QTL) mapping. Chapter 3 builds on the known phenomenon of modified penetrance, where common regulatory variants reduce the pathogenicity of rare coding variants. Ultimately, these three studies will contribute to our knowledge of genome regulation, which will be crucial in a future of personalized medicine.