They suspect it may be a new lineage of the Kashmiri bee virus, but it could be something completely novel.
About 50,000 years ago, a new lineage arose and a population from this lineage migrated out of Africa to southern Asia and Australia.
Researchers will also begin re-examining the fossil collections in museums to see if any wrongly assigned bones might belong instead to the new lineage, Dr. Krause said.
The people of the new lineage presumably wore clothes, Dr. Krause said, because chimpanzees and gorillas cannot withstand much cold, suggesting that fur alone is inadequate protection.
The new lineage is the second such challenge, and it suggests that human migrations out of Africa, though far from continuous, were more frequent than supposed.
The authors' most spectacular discovery is the initiation and establishment of a new lineage that now behaves as a new species, differing from others in size, song, and other characteristics.
Any stem cell that is the progenitor of a new lineage occupies a privileged status.
Recently, a new lineage, highly divergent from the Italian prototype, has been reported in Spain.
Differentiation of these pluripotent cells requires cells to undergo patterns of remethylation that are specific to each new lineage formed.
Phylogenetic analysis has separated the 8 HPeV1 strains as a new lineage from the prototype strain (L02971) in evolutionary transition.
Cavers in the Pacific Northwest have discovered a type of spider so unusual it belongs to an entirely new lineage.
