By Heather Mendiola
In the April 2014 issue of the scientific journal Genetics, a new method of genome analysis led to confidence that Neanderthals interbred with early humans, called Denisovans.
These Denisovans are different from modern humans. Much like the Neanderthals, they died out thousands of years ago, but not before both left genetic evidence in modern human DNA.
The new genome analysis method uses the distribution of the different genealogical histories to estimate relevant parameters in which to compare the sample types.
The new method used small parts of recombinant genome samples from four different types: Neanderthal, European and Asian, African and chimpanzee.
The two main scenarios being debated were: Neanderthals occasionally interbred with humans after they migrated out of Africa, and both the Neanderthals and the humans that migrated out of Africa evolved from the same ancestral subpopulation.
After the comparison, scientists Konrad Lohse and Laurent Frantz were able to accurately reject the scenario that Neanderthals and non-African modern humans were not from the same ancestral subpopulation.
This new method was not only relevant in ending this on-going debate.
“Because the method makes maximum use of the information contained in individual genomes, it is particularly exciting for revealing the history of species that are rare or extinct,” said Lohse.
This study has also opened a channel as to what classifies a species.
As currently defined, organisms of the same species are capable of interbreeding and producing fertile offspring, such as two humans.
The controversy is that Neanderthals are a species of the genus Homo and modern humans are a different species of the genus Homo.
With this new discovery, either the Neanderthals will be moved to a subspecies of Homo sapiens or the definition that dictates that two species cannot produce fertile offspring will need to be altered.