Final answer:
HIV-1 likely originated in sub-Saharan Africa, infecting humans after a zoonotic transmission from monkeys. The virus has caused a devastating pandemic, particularly in Africa, where treatment and prevention are less available. Researchers have found a genetic mutation that provides resistance to HIV, which is most prevalent in northern Europeans.
Step-by-step explanation:
HIV-1, the predominant strain of the Human Immunodeficiency Virus causing the global pandemic of Acquired Immunodeficiency Syndrome (AIDS), is believed to have originated in sub-Saharan Africa during the 20th century. In its early stages, the virus probably infected monkeys before jumping to humans, likely through zoonotic transmission, and eventually leading to a pandemic. As a result of HIV infection, more than 25 million people have died since the first identification in 1981, with sub-Saharan Africa being the most affected region due to a lack of available medicines and prevention strategies.
A genetic mutation called CCR5-delta 32 found in individuals of northern European descent provides resistance to HIV, suggesting historical selective pressures, perhaps from other diseases like the plague or smallpox. This mutation prevents the virus from effectively binding to the T cells, reducing susceptibility to the infection. The discovery of the CCR5-delta 32 mutation has piqued scientific interest and spurred research into its origins and protective effects against HIV infection.