Question

Which of the following is incorrect statement about Building Work of MP tree?

(a) It works by searching for all possible tree topologies and reconstructing ancestral sequences that require the minimum number of changes to evolve to the current sequences

(b) Other than informative sites are non-informative, which are constant sites or sites that have changes occurring only once

(c) Informative sites are the ones that can often be explained by a unique tree topology

(d) Constant sites have the same state in all taxa and are quite useful in evaluating the various topologies

I had been asked this question in an online quiz.

This is a very interesting question from Character Based Methods topic in division Phylogenetic Tree Construction Methods and Programs of Bioinformatics

Answer 1

The correct answer is (d) Constant sites have the same state in all taxa and are quite useful in evaluating the various topologies

To explain I would say: Constant sites have the same state in all taxa and are obviously useless in evaluating the various topologies. The sites that have changes occurring only once are not very useful either for constructing parsimony trees because they can be explained by multiple tree topologies. The non-informative sites are thus discarded in parsimony tree construction.