We have released two preprints exploring mosaic chromosomal alterations in UK Biobank (N~500K; Loh et al. bioRxiv) and BioBank Japan (N~200K; Terao et al. bioRxiv). Highlights of these studies include discovery of several new risk loci at which acquired mutations systematically duplicate inherited rare coding variants, a polygenic effect in which clonal selection acts on mutant cells that have increased polygenic drive for blood-cell proliferation traits (by replacing one chromosome arm with its homologous counterpart), and population differences in genomic locations of hematopoietic clones mirroring epidemiological differences in rates of B- and T-cell cancers.