If you suffer from allergies, the fault is in your genes, a DNA factor caused by the sharing of a bed with humans and their brawny cousins, the Neanderthals, or their close relatives, the Denisovans. The gene has made the human more susceptible to sneezes, itches and other forms of allergies.
It will look indecent that Homo sapiens once interbred with the primitive, ancient cousins Neanderthals.
We know that tens of thousands of years ago the Neanderthals and another ancient species, the Denisovans not only interbred, but they did it frequently and successfully to give the modern day Homo Sapiens, 1 to 2 % of his DNA. It took six years and some projects to map out the Neanderthal and human genomes to know that a little hanky panky was going on some tens of thousands ago.
However, this inheritance has turned out to be a double-edged sword – a blessing and a curse in the same breath.
A study has been published in the American Journal of Human Genetics, and it is the part of the same genome mapping projects that linked humans to Neanderthals.
Now the same study has revealed that three genes of Neanderthals, or their close relatives, the Denisovans is essential to our immune system, in both situations, when it is working and when it is going haywire.
This superior immune system got a head start in the evolutionary race, and the traits were quickly dispersed through the human population. But the process of evolution is very cruel because it also made the big-brained, better-adapted humans armed with immunity inherited ultimately lead to the extinction of the species whose DNA it found useful.
But long dead species can extract its pound of flesh and in this case, it is hay fever and cat allergies that humans have to deal. Increased sensitivity to potential pathogens also made the reactive to things that are not pathogenic like pollen and pet hair.