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
- Newts produce tetrodotoxin (TTX), a poison that targets sodium ion channels, for defense against their predators, garter snakes. Several species of garter snakes are resistant to newt TTX due to specific known amino acid substitutions in garter snake sodium channels. Which one of the following is best-suited to identify whether this adaptation in garter snakes has a single origin or multiple independent origins?
A phylogenetic tree representing the evolutionary relationship between various vertebrates is shown below.
Given this tree topology, which one or more of the following statements is/are correct?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?- 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?
In the phylogenetic trees shown, the tips represent different species of geckos(labeled A to E) and the areas to which they belong. Which one of these is most consistent with the hypothesis that the geckos colonized the Western Ghats from Northeast India through the Eastern Ghats?
