The phylogeny below shows the relationship between six species based on whole genome data. The sequence of a part of a particular gene from each species is provided at the tips of the tree. Based on the principle of parsimony, which one of the following is the expected sequence for the ancestor X?
To determine the ancestral sequence at point X, we use the principle of parsimony. Parsimony suggests selecting the simplest evolutionary pathway, that is, the pathway requiring the fewest changes.
Let's analyze the sequence alignment at each position of the sequence across the given species.
Here are the sequences:
- Species 1: ATGG
- Species 2: AAGG
- Species 3: AACG
- Species 4: AACT
- Species 5: ATGG
- Species 6: ATCG
Now, we analyze each position in the sequence:
- The first position: A occurs in all sequences.
- The second position: T (3 times), A (3 times). The most parsimonious choice is A, since it's present in a clade containing three species.
- The third position: G (2 times), C (4 times). The most parsimonious choice is C.
- The fourth position: G (4 times), T (1 time), C (1 time). The most parsimonious choice is G.
Thus, the most parsimonious ancestral sequence for X is AACG, as it requires the fewest evolutionary changes from the descendant sequences while accounting for the observed variation.
Hence, the correct answer is AACG.
Important Questions from Phylogenetic trees
Which one of the following phylogenetic trees illustrates the relationship between Archaea, Bacteria and Eukarya?
The phylogeny of six species of birds is illustrated below, where the horizontal branch lengths correspond to genetic distance. These six species are distributed in three islands X, Y, and Z. Island X harbours species 1, 4, 6; Island Y harbours species 1, 2, 4; and Island Z harbours species 3, 4, 5. Which one of the following is true about the phylogenetic diversity of these islands?
A phylogenetic tree for the evolution of two pigmentation traits in species of fish is shown for clades X, Y and Z. Genes A and/or B, if mutated, can cause dark pigmentation in the body.
Which one or more of the following statements is/are correct?- Which of the following trees is phylogenetically MOST accurate?
- Whales and dolphins are hypothesized to have evolved along the northern shore of the Tethys Sea, prior to the Indian plate's collision with the Eurasian plate. To which one of the following animals are these aquatic mammals most closely related?
