Question 8: Calculate the mean sum from the tip of a branch to the common ancestor of Group M. (To view the branch lengths on the tree select "Substitutions per site" from the dropdown box next to "Display" under "Show Branch Labels") > |
Question 9: Assuming that the substitution rate of HIV-1 is approximately 10-5 substitutions per nucleotide site per generation, use the mean sum of branch lengths to calculate how many HIV-1 generations have elapsed since the Group M sequences diverged from a common ancestor. > |
Question 10: An HIV-1 generation lasts about 2 days. This is the time it takes for a virus particle to infect a cell and produce new virus particles ready to infect new cells. From this generation time, calculate how many years ago the Group M sequences diverged from a common ancestor. > |
Question 11: Approximately in which year did the HIV-1 pandemic sequences originate assuming the average sampling year was 1990? > |
Question 12: Which of the above hypotheses about when the pandemic sequences originated does your result support? > |