Class: Introduction to Evolution
Topic: Mutation
Question:
How would you expect selection against mutations to impact the slope of a best-fit line of genetic differences between two virion populations? The slope would:
a) increase
b) decrease
c) stay the same
This is some information some other questions for this topic (Molecular clock)
- Now click the FIT LINE button and look at your best fit line. It shows how rapidly genetic differences have been accumulating between your two patients while you have been watching. You can also follow the line back to get an idea of what was happening before you started watching. It is dangerous to use a best fit line to extrapolate beyond the range of the data, but in this case the best fit line is all we have. Look to the right of the graph to find both the slope of this line (which you used in earlier exercises), and the y-intercept, which is labeled Intercept. [ 7.1 ] Write the equation of your best fit line here (use the standard form, y = mx + b).
Keep in mind that y (the dependent variable) is the number of sequence differences, and x (the independent variable) is the generation number. We want to use the previous equation to estimate the time (i.e., the generation) Patient 2 acquired HIV from Patient 1. When would that have been? It would have been the point in time when the genetic difference between viral populations in your two patients was zero. To make your estimate, substitute y = 0 in your best fit line equation and solve for x.