What is the function of an outgroup in phylogenetic tree construction?
- A
To assess homology between analogous traits
- Bcheck_circle
To root the tree and polarize ancestral vs derived character states
- C
To exclude horizontally transferred genes
- D
To represent the most recent common ancestor of the ingroup
Explanation
An outgroup is a taxon known to lie outside the group of interest. It allows researchers to root the tree and identify which character states are ancestral (shared with outgroup) versus derived.