A previously unknown type of human ancestor was discovered when 50,000
year old finger bones and a tooth from Denisova cave in Southern
Siberia were mtDNA tested.
The results showed that the bones were of people neither modern human
nor Neanderthal. Comparison of their DNA with modern human groups' DNA
showed that around 5% of Melanesians may be descended from the
Denisovans, as they are being called.