Detecting and quantifying clonal selection in somatic mosaicism

In this study, we introduce a scalable method to identify clonal selection in an individual tissue, agnostic of the underlying mutations. To study clonal selection in the haematopoietic system, we performed whole genome sequencing on bone marrow CD34+ haematopoietic stem and progenitor cells from 22 non-leukemic individuals, 30-89 years of age. We performed 90x whole genome sequencing for all samples and re-sequenced 19 samples with sufficient DNA to a total target coverage of 270x. Whole genome sequencing of hair follicle DNA from the same individuals was used as germline control. In addition, we sequenced unseparated bone marrow mononuclear cells, CD3-CD34- bone marrow mononuclear cells, and peripheral blood granulocytes from 14 samples. Samples were collected from individuals undergoing hip replacement surgery as part of the Mechanisms of Age-Related Clonal Haematopoiesis (MARCH) Study (REC Ref: 17/YH/0382).EGA study EGAS00001007558