Figure 1.

Schematic of the Whole-Genome In-Solution Capture Process

To generate the RNA “bait” library, a human genomic library is created via adapters containing T7 RNA polymerase promoters (green boxes). This library is subjected to in vitro transcription via T7 RNA polymerase and biotin-16-UTP (stars), creating a biotinylated bait library. Meanwhile, the ancient DNA library (aDNA “pond”) is prepared via standard indexed Illumina adapters (purple boxes). These aDNA libraries often contain <1% endogenous DNA, with the remainder being environmental in origin. During hybridization, the bait and pond are combined in the presence of adaptor-blocking RNA oligos (blue zigzags), which are complimentary to the indexed Illumina adapters and thus prevent nonspecific hybridization between adapters in the aDNA library. After hybridization, the biotinylated bait and bound aDNA is pulled down with streptavidin-coated magnetic beads, and any unbound DNA is washed away. Finally, the DNA is eluted and amplified for sequencing.