Correct option is A
Regeneration involves different mechanisms across organisms, including blastema formation, morphallaxis, and compensatory regeneration. Let's analyze each statement carefully.
Analysis of Statements:
Statement A: Correct
- In amphibians, regenerating blastema cells retain their specification even after dedifferentiation.
- Although cells lose their original differentiated state, they maintain a memory of their lineage, meaning muscle cells regenerate muscle, cartilage cells regenerate cartilage, etc.
- This lineage restriction ensures correct tissue regeneration.
- This statement is correct.
Statement B: Incorrect
- β-catenin misexpression in Hydra leads to excessive Wnt signaling, but it does not necessarily cause numerous ectopic tentacles.
- While Wnt activation can lead to axis duplication and head formation, ectopic tentacle formation is not a direct consequence of β-catenin misexpression alone.
- This statement is incorrect.
Statement C: Incorrect
- In Planaria, Wnt signaling controls anterior-posterior polarity.
- However, activation of Wnt in the posterior blastema does NOT regenerate a head, but rather promotes tail formation.
- If Wnt is inhibited in the posterior region, a head forms instead of a tail.
- Since this statement reverses the actual role of Wnt in Planaria, it is incorrect.
Statement D: Incorrect
- Mammalian liver regeneration does not involve blastema formation.
- Instead, it occurs through compensatory hyperplasia, where hepatocytes proliferate to replace lost liver mass without dedifferentiation.
- Since a blastema is not formed, this statement is incorrect.
