Fig. 4: Selection against nonsynonymous mtDNA variants occurs at the level of cell fitness.
From: Single-cell analysis reveals context-dependent, cell-level selection of mtDNA
a, Schematic overview of the lineage tracing experiment. 293T cells were transfected with LHON or SILENT DdCBEs and subsequently transduced with a lentiviral library with unique ancestry barcodes so that each heteroplasmic cell expressed a single, unique ancestry barcode. Ancestral lineages were expanded, cells were harvested at day 0 and day 5, and multiplexed SCI-LITE was performed to capture mtDNA heteroplasmy and ancestry barcodes. Schematics in part a were creating using BioRender (https://biorender.com). b, Distribution of differences in heteroplasmy levels between day 5 and day 0, for all ancestral lineages that were detected at both days. c, Heteroplasmy levels in randomly selected ancestral lineages at day 0 and day 5. Each line represents one unique ancestral lineage and visualizes the mean heteroplasmy level at each day. See Extended Data Fig. 8 for all ancestral lineages. d, Single-cell heteroplasmy in LHON-edited cells. The graphs show empirical cumulative distributions of missense heteroplasmy in ancestry lineages found at only one timepoint or at both timepoints. The Kolmogorov–Smirnov test was used to calculate D statistics and P values. e, Relative frequency of binned missense heteroplasmy in ancestral lineages found at day 0 only or at both timepoints. Cells with ancestry barcodes that are found only at day 0 have significantly higher missense heteroplasmy by Kolmogorov–Smirnov test, suggesting cell-level selection against these lineages.
