Extended Data Fig. 1: Mosaic chromosomal alterations detected among 482,789 UK Biobank participants.

a, Each horizontal line corresponds to an mCA; a total of 19,632 autosomal events in 17,111 unique individuals are displayed. Detected events are colour-coded by copy number of the affected chromosome or segment (orange, LOH; blue, loss/deletion; red, gain/duplication). Focal deletions are labelled in blue with the names of putative target genes. Loci containing inherited variants influencing somatic events in cis are labelled in the same colour as the corresponding mCA (orange for CN-LOH-associated loci, blue for losses). b, Sex and age distributions of individuals with detected mosaic events. Marker size and colour intensity increase with event frequency. Error bars denote 95% confidence intervals. Sample sizes are provided in Supplementary Table 1 and numeric data are provided in Supplementary Table 4. Three events with unusual sex biases (gains on chromosome 15, 16p11.2 deletions and 10q terminal deletions) were previously reported⁹, all of which replicated here. We have not identified a mechanism that could explain the sex biases. The overall tendency of male enrichment for most mCAs raises the possibility that environmental exposures could result in genomic insults that lead to mCAs; however, the heterogeneity of the level of male enrichment across different mCAs suggests that the mechanisms producing sex biases may be event-specific. c, Enrichment of mosaic chromosomal alterations in individuals with anomalously high blood indices. Different mCAs are significantly enriched (FDR of 0.05; one-sided Fisher’s exact test) among n = 455,009 individuals with anomalous blood counts in different blood lineages (adjusted for age, sex and smoking status). Events were grouped by chromosome and copy number, with loss and CN-LOH events subdivided by p-arm versus q-arm. (We did not subdivide gain events by arm because most gain events are whole-chromosome trisomies.) Numeric data are provided in Supplementary Table 5.