Question

In phylogenetic tree construction, which method is distance-based?

• A. Maximum likelihood
• B. Maximum parsimony
• C. Neighbor-joining
• D. Bayesian inference

Hint:

Remember the classification of phylogenetic methods: \[ \boxed{\text{Neighbor-Joining} \rightarrow \text{Distance-Based}} \] \[ \boxed{\text{Maximum Parsimony, Maximum Likelihood, Bayesian} \rightarrow \text{Character-Based}} \] Neighbor-Joining is preferred when analyzing large datasets because it is faster than most character-based methods.

Answer 1

The Correct Option is C

Concept: Phylogenetic trees represent the evolutionary relationships among different organisms or genes. Various computational methods are used to construct these trees. Among them, the Neighbor-Joining (NJ) method is a distance-based algorithm that constructs trees using genetic distance data.
• Distance-based methods first calculate evolutionary distances between sequences.
• Neighbor-Joining builds the tree by joining the closest neighboring taxa.
• It is computationally fast and suitable for large datasets.
• It produces an unrooted phylogenetic tree.

Step 1: Understand the Neighbor-Joining method.
The Neighbor-Joining algorithm works as follows:
• Calculate pairwise evolutionary distances.
• Identify the two closest taxa.
• Join them into a single cluster.
• Recalculate distances.
• Repeat until the complete phylogenetic tree is formed. Thus, the method is entirely based on genetic distance.

Step 2: Differentiate from other methods.

• Maximum Parsimony selects the tree requiring the fewest evolutionary changes.
• Maximum Likelihood uses probability models to estimate the most likely tree.
• Bayesian Inference applies Bayesian statistics and posterior probabilities.
• Neighbor-Joining alone is classified as a distance-based method.

Step 3: Choose the correct option.
Therefore, \[ \boxed{Option (C) is the correct answer. \]