IGHD and B-cell chronic lymphocytic leukemia: Using these cutoffs, on average for each sample 2.3 million reads met our filtering criteria (effective “sequencing depth” = 2,300,000×) carrying 0.4 million distinct UMIs representing 540 unique nucleotide sequences (intraclonal subclones) for an individual CLL IGHV-IGHD-IGHJ rearrangement.