Background Information: The NIH Intramural Sequencing Center (NISC) is a centralized research facility for performing high-throughput, large-scale DNA sequencing and sequence analysis. We have been in operation since 1997. We supply state of the art sequencing services to institutes throughout the NIH. NISC houses a unique sequencer from Ultima Genomics that provides rapid high-volume sequencing at low cost. When patients have a mixture of DNA sequences in their bodies they are called mosaic. One of the sequences can be highly underrepresented requiring deep sequencing to find. The depth of sequencing is limited by the accuracy of the sequencing. Ultima Genomics has a highly accurate sequencing method that allows us to look much deeper for the second genome