Scientists have found that important types of genes responsible for immunity in modern humans were obtained from the Neanderthals.

Until 2008, it was our belief that the modern human never mated with the Neanderthal. Then the scientists found scientific evidence to prove that such mating did take place. This research had concluded that this interbreeding which took place in the prehistoric times have resulted in 4% of the modern human genome. Scientists have concluded that many important elements of the immune system presently enjoyed by the modern human have been derived from the Neanderthal.

Mating with another ancient group called Denisovans is also reported to have caused the introduction of genes which are essential for our immune system.

Within the human immune system there is a specific family of genes which will plays a major part in defending our bodies from being invaded by foreign organisms like viruses. They form the human leucocyte antigen (HLA). Scientists have noted that the origin of certain HLA class 1 genes will be able to prove the fact that interbreeding did happen between Neanderthals and our ancient relatives.

It has been noted that as a minimum a single type of HLA gene is occurring commonly within the current population in West Asia. However, this is rarely found among the Africans. Scientists have reported that the reason for this is that about 65,000 years ago the ancient human had left Africa and begun to breed with those in Europe who were their more primitive relations. Those who stayed in Africa did not undergo such breeding.

The HLA genes that the Neanderthals and Denisovans had, had been adapted to life in Europe and Asia for several hundred thousand years, whereas the recent migrants from Africa wouldn't have had these genes, said study leader Peter Parham from Stanford University School of Medicine in California, reported BBC.

There will be further research required to make a final conclusion on this aspect since there are divisions among scientists on whether interbreeding has helped our immune system. Scientists are agreeing on the fact that interbreeding did take place. However, there are on-going debates on the impact of such interbreeding.