640,000 years ago, and the time between both of these and the sequences of modern Africans is 804,000 years ago. They suggest the divergence of the Denisova mtDNA results either from the persistence of a lineage purged from the other branches of humanity through genetic drift or else an introgression from an older hominin lineage. Homo heidelbergensis Homo heidelbergensis was first discovered in 1907 near Heidelberg, Germany and later also found elsewhere in Europe, Africa, and Asia. However it was not until 2013 that a specimen with retrievable DNA was found, in a ~400,000 year old femur found in the Sima de los Huesos Cave in Spain. The femur was found to contain both mtDNA and nuclear DNA. Improvements in DNA extraction and library preparation techniques allowed for mtDNA to be successfully isolated and sequenced, however the nuclear DNA was found to be too degraded in the observed specimen, and was also contaminated with DNA from an ancient cave bear (Ursus deningeri) present in the cave. The mtDNA analysis found a surprising link between the specimen and the Denisovans, and this finding raised many questions. Several scenarios were proposed in a January 2014 paper titled "A mitochondrial genome sequence of a hominin from Sima de los Huesos", elucidating the lack of convergence in the scientific community on how Homo heidelbergensis is related to other known hominin groups. One plausible scenario that the authors proposed was that the H. heidelbergensis was an ancestor to both Denisovans and Neanderthals. Completely sequenced nuclear genomes from both Denisovans and Neanderthals suggest a common ancestor approximately 700,000 years ago, and one leading researcher in the field, Svante Paabo, suggests that perhaps this new hominin group is that early ancestor. Applications Discovery and characterization of new species Molecular paleontology techniques applied to fossils have contributed to the discovery and characterization of several new species, including the Denisovans and Homo heidelbergensis. We have been able to better understand the path that humans took as they populated the earth, and what species were present during this diaspora. De-extinction It is now possible to revive extinct species using molecular paleontology techniques. This was first accomplished via cloning in 2003 with the Pyrenean ibex, a type of wild goat that became extinct in 2000. Nuclei from the Pyrenean ibex's cells were injected into goat eggs emptied of their own DNA, and implanted into surrogate goat mothers. The offspring lived only