The genetic architecture of cell-type-specific cis-regulation

Gene expression and complex phenotypes are determined by the activity of cis-regulatory elements. However, an understanding of how extant genetic variants affect cis-regulatory activity remains limited. Here, we investigated the consequences of cis-regulatory diversity using single-cell genomics of >0.7 million nuclei across 172 maize inbreds. Our analyses pinpointed cis-regulatory elements distinct to domesticated maize and how transposons rewired the regulatory landscape. We found widespread chromatin accessibility variation associated with >4.6 million genetic variants with largely cell-type-specific effects. Variants in TEOSINTE BRANCHED1/CYCLOIDEA/PROLIFERATING CELL FACTOR binding sites were the most prevalent determinants of chromatin accessibility. Finally, integration of genetic variants associated with chromatin accessibility, organismal trait variation, and population differentiation revealed how local adaptation has rewired regulatory networks in unique cellular context to alter maize flowering phenotypes.