Figure 1.

Cloning strategy for constructing and analyzing metagenomic libraries using DNA extracted from cave bear tooth and bone (adapted from [12]). Total DNA from the samples, which will include numerous environmental contaminants, is isolated and cloned. After the cloned DNA was extracted and sequenced, the sequences are analyzed using BLAST against available databases to distinguish the relatively few cave bear clones (red) from the rest of the DNA. In this case, a similarity to canine DNA (unlikely to be a contaminant) was used to identify candidate cave bear DNA.