A highly scalable method for joint whole genome sequencing and gene expression profiling of single cells

Abstract

Understanding how genetic variation alters gene expression - how genotype affects phenotype - is a central challenge in biology. To address this question in complex cell mixtures, we developed Direct Nuclear Tagmentation and RNA-sequencing (DNTR-seq), which enables whole genome and mRNA sequencing jointly in single cells. When applied to biobanked leukemia samples, DNTR-seq readily identified minor subclones within patients, as well as cell-type specific gene editing such as T-cell receptor rearrangements. mRNA-seq quality is equal to RNA-only methods, and the high yield combined with low positional bias of the genomic library preparation allows detection of sub-megabase aberrations at ultra low coverage of 0.5-3M read pairs per genome. Since each cell library is individually addressable, rare subpopulations can be re-sequenced at increased depth, allowing multi-tiered study designs where depth of sequencing is informed by previous results. In addition, the direct tagmentation protocol enables coverage-independent estimation of ploidy, which can be used to unambiguously identify cell singlets. Thus, DNTR-seq directly links each cells state to its corresponding genome at a scale enabling routine analysis of heterogeneous tumors and other complex tissues.