Explain the importance and utility of including an outgroup

Explain the importance and utility of including an outgroup in phylogenetic analyses

Solution

An outgroup is a taxon outside the group of interest. All the members of group are more closely related to each other than they are related to outgroup. An outgroup forms the base of tree. It serves as a reference in determining the evolutionary relationship among the other monophyletic groups of organisms. It is used as a point of comparison for the groups. It allows the set of groups in the phylogenetic tree to be rooted.