Cave bears roamed Western Europe about 250,000 years ago and became extinct around 12,000 years ago. James Noonan and Edward Rubin at Berkeley National Laboratory, CA, extracted DNA from 40,000-year-old cave bear samples using a novel metagenomic approach. This technique avoids polymerase chain reaction (PCR), which selectively amplifies modern DNA contaminants over ancient sequences. After cloning all of the sample’s DNA in bulk, powerful computer analyses were used to identify the tiny fraction of ancient DNA in the mix. Six percent of the DNA recovered showed about 97% identity with DNA from modern brown bears – supporting the validity of metagenomics for recovering ancient DNA from complex samples.
Did you know? Cave bears lived in the same spaces coveted by prehistoric humans in Europe around 32,000 years ago.