534. A massively parallel reporter assay to screen bovine regulatory variants

Abstract

Differentiating causative variants from linked variants is a major challenge of modern genetics. Here, we describe development of a massively parallel reporter assay (MPRA), an in vitro method that enables simultaneous functional testing of thousands of candidate causative regulatory variants. Candidates for the MPRA were identified through analysis of two large molecular quantitative trait loci (QTL) datasets derived from sequencing of bovine mammary biopsies, comprising an expression QTL resource (n=371 cows), and a histone QTL dataset (n=99 cows). Candidates that overlapped with lactation QTL discovered from genome-wide association studies were further prioritised to yield a final library of 242,340 oligos representing 24,234 regulatory sequences for expression testing. This paper gives a brief description of the MPRA method, our candidate selection criteria, cloning approach, and the composition of the final oligo pool for expression analysis.