Korb et al. (2000) obtained blood samples extracted fom patients infected with HIV-1 strain M. The blood samples were taken from the patients from the 1980s through the 1990s. Korb et al. (2000) genotyped the blood samples and plotted the genetic differences among all of the samples against the time the samples were taken. This analysis indicated that _________________. the first time a human was infected with HIV-1 was sometime between 1920 and 1940 the first human to be infected with HIV-1 was probably due a bite from a bat the first time a human was infected with HIV-1 was sometime between 1970 and 1980 HIV-1 arose in a person in which a mutation converted HIV-2 to HIV-1 .