Ancient people were deprived of two genes to survive the epidemic infection
About 100,000 years ago, the human species is on the brink of extinction (number has decreased to less than 10,000). However, in a few thousand years, man gained a foothold on the world. Recent genetic studies have shown that all these variations is an epidemic of bacterial infection, says New Scientist.
Bacteria in question, had an impact on the immune system of the two genes, turning them against the person. Then the body has decided to get rid of these genes. According to Ajit Varki of the University of California, the "culprit" may well be genes Siglec-13 and Siglec-17.
They are involved in the control of immunity, being active in the chimpanzee, but "off" in humans. Siglec-13 is completely missing from the human genome, and Siglec-17 is not working, so he lost a single letter code.
Researcher reconstructed the lost protein and found that two dangerous bacteria – streptococcus group B and E. coli K1 – are to be joined. These pathogens are especially dangerous for infants.
Experiment with modified cells proved that the cells experienced a reduced immune response to bacteria. That is, the bacteria suppressed immune system, tied to two hapless proteins. Rather, saving changes in the human genome occurred 440000-270000 years ago.