An Introduction to Phylogenetic Analysis - Association for Biology ...

Table 7. More complete shared character table for Example C1.
Phylogenetic Analysis 71
Shared
Characters
A B C D E F
Species Branched Off Before
Shared Characters Evolved
8 X X X X X X Outgroup
6, 11 X X X X A, D
5, 20 X X X B
Remaining C, E, F
After characters 5 and 20, we can’t go any further with the Shared Character Table because there is
no clear choice for the next most common shared character. Therefore, we’ll list C, E, F (the remaining
species) as the last branched group. Our cladogram now looks like this:
OG (A, D)
Figure 12. A more complete cladogram for Example C1.
B
8
(C, E, F)
Note that we do the cladogram by writing a branch for the “Branched Off” group and then putting
the common character(s) from that line on the main diagonal after the branch. So the OG branch is
followed by character 8, the (A, D) branch is followed by common characters 6 and 11, and the B
branch is followed by common characters 5 and 20. These steps will allow you to complete the main
outlines of the cladogram.
We’ll have to resolve the (A, D) and (C, E, F) groups by some parsimonious guessing. We’ll
rewrite the character matrix with A and D listed together and C, E, and F listed together. We won’t
include species B because it is not involved in a group with undetermined relationships.
6
11
5
20