Integrating natural and engineered genetic variations to decode regulatory influence on blood traits.

Understanding the function of genetic variants associated with human traits and diseases remains a significant challenge. Here, we combined analyses based on natural genetic variation and genetic engineering to dissect the function of 94 non-coding variants associated with hematological traits. We describe 22 genetic variants impacting hematological variation through gene expression. Further, through in-depth functional analysis, we illustrate how a rare, non-coding variant near the CUX1 transcription factor impacts megakaryopoiesis through the modulation of the CUX1 transcriptional cascade. Collectively, our findings enhance the functional interpretation of genetic association studies and advance understanding of how non-coding variants contribute to blood and immune system variation.