To validate this approach, we created in silico admixtures by diluting reads from plasma WGS of a CRC or melanoma patient into their matched peripheral blood mononuclear cells WGS to maintain SNP phasing consistency (Supplementary Table 4), identifying allelic imbalance signal in TF admixtures as low as 5*10-5 (Fig. 2c, Extended Data Fig 4a, middle). Here, TF is linked to melanoma.