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?
To determine the homology of the pigmentation trait in the given species, we need to analyze the phylogenetic tree. Homologous characteristics are those that are inherited from a common ancestor. Let's examine the traits across different clades:
Analysis:
-
Species 1 and 3: Both species are within Clade X. They share a common ancestor in this clade that had the gene A responsible for pigmentation. Since the pigmentation in both species is derived from this shared ancestor, the pigmentation is homologous.
-
Species 1 and 4: Species 4 belongs to Clade Y, which diverged after Clade X. The pigmentation trait in species 4 is caused by gene B, different from the ancestor in Clade X with gene A. Thus, the pigmentation is not homologous.
-
Species 6 and 7: Both are in Clade Z, but neither presents pigmentation. As there is no characteristic to compare for homology, the pigmentation is not homologous.
-
Species 2 and 6: These species belong to different clades (Clade X and Clade Z, respectively) and have different genetic causes or lack thereof for pigmentation. Clade X has pigmentation due to gene A, while Clade Z lacks pigmentation entirely. Therefore, the pigmentation is not homologous.
Conclusion: The correct statements from the options are:
- The character state “pigmentation” is homologous in species 1 and 3.
- The character state “pigmentation” is not homologous between species 2 and 6.
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?
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?
- 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?
