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
- 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?- 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?
The phylogenetic tree depicts the relationship between 5 species of snakes(labelled A to E) and provides information about their habitat specialization. Given the principle of parsimony (least number of evolutionary changes required)and that ancestor Y was terrestrial, which one of the options given is correct?
