John Harshman on October 13, 2017 at 11:12 pm said:
Here is an explanation of Sal’s favorite figure. The trees each represent one of the areas in the Venn diagram, with the most parsimonious interpretation (or one of them if there are several) represented for each. I only had room for 8 of the 15 areas, but the others are similar. A red bar represents gene loss and a green bar represents gene gain. Every tree with only one bar fits the tree perfectly and supports the nested hierarchy. Every tree with two bars doesn’t fit the tree perfectly. Note, however, that the one-bar trees all have many more genes than the two-bar trees, as if the probability of two events on a tree is much less than the probability of one event. Of course that only makes sense if there’s a tree. Otherwise there is no explanation for the differences in number among areas of the diagram. See, phylogeny does explain stuff.
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