Question

evolutionary distance is a measure of the time two lineages have been diverging. it is calculated by adding the branch lengths of the two lineages starting at the most recent common ancestor. for example, if lineage 1 has been evolving for 2 years and lineage 2 has been evolving for 2 years, the evolutionary distance between the lineages is 4 years. what is the evolutionary distance between viruses a and b?

Explanation:

Step1: Identify the divergence time

From the tree, viruses A and B diverged from their most - recent common ancestor in 2010.

Step2: Calculate the branch lengths

Since both viruses A and B have been evolving for 10 years (from 2010 - 2020).

Step3: Calculate the evolutionary distance

The evolutionary distance is the sum of the branch lengths of the two lineages starting at the most - recent common ancestor. So, \(10 + 10=20\) years.

Answer:

20 years