Question

What is Totipotency?

Answer 1

Hint: The latin word of totipotency is totipotential ‘’ability for all things ‘’. Totipotential is the ability to regenerate organs or tissue.

Complete Answer:
- The original test of totipotency was performed in mice by Tarkowski, who isolated a single blastomere i.e. cells created by division of the zygote, consisting of $2 - 16$ cells.
- The totipotency is the ability of a cell, such as an egg, to give rise to generate a new organism or part. The ability of cells such as an embryonic stem cell to differentiate into any type of body cell. Plant cells are also totipotent, which helps to explain why a graft of a plant can generate a whole new individual out of just a small branch.
- Stem cells are characterized according to their degree of potency, which refers to their varying ability to differentiate into different cell types. Totipotent cells are the most potent of all stem cells, and dying them is important for research and the field of regenerative medicine.

Some factors that affect totipotency are:
1. Source of explant: Organ that serves as tissue source, physiological and ontogenic age of organ, season in which explant is obtained, size, overall, quality of explant.
2. Nutrient media and constituent’s: Micronutrients carbon/energy source, reduced nitrogen source, plant growth regulator.
3. Cultural environment (Physical form of medium): pH of medium, light quality and quantity, temperature, relative humidity and gaseous atmosphere in the vessels.

Note: Totipotent stem cells differ from pluripotent cells, which can differentiate into cells from any of three germ layers, and multipotent cells which are less potent.