An international group of paleontologists and biologists announced the sequencing of the genome of the Middle Pleistocene cave bear (Ursus deningeri) using a new method that produces a complete genome from small DNA fragments in the Sept. 9, 2013, edition of the journal Proceedings of the National Academy of Sciences.
This is the first known sequencing of any animal’s genome outside of the permafrost. Frozen fossils maintain more integrity in their DNA and produce longer strands of DNA that are intact making genomic analysis easier. Specimens that are not frozen demonstrate a breakdown in DNA to short fragments that make a complete genetic analysis difficult.
The bone used in the analysis was excavated at Sima de los Huesos in the Sierra de Atapuerca, Spain and is 300,000 years old. The animal is a sister lineage of all Western European Late Pleistocene cave bears based on phylogenetic reconstruction.
The fossil contained only fragments of DNA that were between ten and 50 base pairs in length. The researchers developed new methods and refined existing methods to arrange and define the genome of an unfrozen fossil of 300,000 years of age for the first time. The protocols used also enabled the researchers to develop the first mitochondrial sequence assembly for any specimen that had not been frozen.