The figure shown is a phylogeny created with DNA sequence data and has high bootstrap support values. The tree also includes observed phenotypes (in varying shades of gray) for the five taxa. The character states are indicated by "B" or "b," "G" or "g," and "P" or "p." Evaluate the hypothetical phylogenetic tree using a parsimony approach. What is the minimum total number of state changes necessary to describe the observed distribution of characters in the taxa?
A) four
B) five
C) six
D) seven

Question

The figure shown is a phylogeny created with DNA sequence data and has high bootstrap support values. The tree also includes observed phenotypes (in varying shades of gray) for the five taxa. The character states are indicated by "B" or "b," "G" or "g," and "P" or "p." Evaluate the hypothetical phylogenetic tree using a parsimony approach. What is the minimum total number of state changes necessary to describe the observed distribution of characters in the taxa? 
A) four 
B) five 
C) six 
D) seven

Quizplus · Accepted Answer

The minimum total number of state changes necessary to describe the observed distribution of characters in the taxa is five. This can be determined by tracing the character state changes along the branches of the tree. For example, to explain the distribution of the "P" character state, two state changes are necessary: one from "P" to "p" in Taxon 2 and another from "p" to "P" in Taxon 4. Likewise, three state changes are necessary to explain the distribution of the "B" character state (one from "B" to "b" in Taxon 2, one from "b" to "B" in Taxon 3, and one from "B" to "b" in Taxon 5). Therefore, the minimum total number of state changes is five.

The Figure Shown Is a Phylogeny Created with DNA Sequence