Final answer:
Modern Europeans and Middle Eastern populations have between 1 and 4 percent Neanderthal DNA, indicating common mating between Neanderthals and Homo sapiens. Neanderthal DNA segments that were beneficial in prehistoric times can now increase the risk of certain diseases. Medical conditions, immune responses, and susceptibility to viruses can be linked to Neanderthal DNA.
Step-by-step explanation:
Modern European and Middle Eastern populations have between 1 and 4 percent Neanderthal DNA, suggesting that mating between Neanderthals and Homo sapiens was quite common. DNA evidence also indicates that some modern humans have inherited Neanderthal DNA segments that were beneficial in prehistoric times, but may increase the risk of certain diseases in today's lifestyle. Research has shown that certain medical conditions, immune responses, and even susceptibility to viruses can be linked to Neanderthal DNA.