BIOL 1082 Lecture Notes - Lecture 8: Tiktaalik, Collagen, Molecular Clock
Document Summary
Phylogenic analysis shows that hiv is descended from viruses that infect chimpanzees and other primates. It is hard to pinpoint when hiv first spread to humans because because it has spread to humans more than once. The multiple origins of hiv are reflected in the variety of strains of the virus. Hiv"s genetic material is made of rna, and like other rna viruses, it evolves quickly. Hiv-1 m. researchers compared samples of the virus from various time during the epidemic. A comparison of gene sequences showed that the virus has evolved in a clocklike fashion. Extrapolating backward in time using the molecular clock indicates that the hiv-1 m strain first spread to humans around 1930. Another study that used a more advanced molecular clock approach estimated that the hiv-1 m strain first spread to humans around 1910: malaria, sickle cell anemia, ebola: ebola is experiencing plenty of mutations.
