Practice Questions

TLS Online TPP Program

#Question id: 7231

Kragl and colleagues (2009) performed an experiment in which they transplanted limb tissue from a salamander whose cells expressed green fluorescent protein (GFP) into different regions of limbs of normal salamanders that did not have the GFP transgene. If they transplanted the GFP-expressing limb cartilage into a salamander limb that did not contain the GFP transgene, the GFP-expressing cartilage would integrate normally into the limb skeleton. They later amputated the limb through the region containing GFP-marked cartilage cells. The blastema was found to contain GFP-expressing cells, and when the blastema differentiated, the only GFP-expressing cells found were in the limb cartilage. Similarly, GFP-marked muscle cells gave rise only to muscle, and GFP-marked epidermal cells only produced the epidermis of the regenerated limb. Which of the following phenomenon is proved according to experiment?

#Unit 5. Developmental Biology

These results suggest that nAG alone is the primary mitogen responsible for nerve-dependent regeneration.
The blastema is not a collection of unspecified multipotent progenitor cells. Rather, the cells retain their specification, and the blastema is a heterogeneous assortment of restricted progenitor cells.
The blastema is a collection of unspecified multipotent progenitor cells. Rather, the cells lost their specification, and the blastema is a homogeneous assortment of restricted progenitor cells.
Salamanders accomplish epimorphic regeneration by cell dedifferentiation to form a regeneration blastema, which in this case is an aggregation of relatively undifferentiated cells derived from the originally differentiated tissue that then proliferates and redifferentiates into the new limb parts.