Question

During embryonic development, the establishment of polarity along anterior/posterior/dorsal/ventral or medical/lateral axis is called

• A. Organiser phenomenon
• B. Axis formation
• C. Anamorphosis
• D. Pattern formation

Answer 1

Answer: (B)

Axis formation

All vertebrate eggs are strongly polar structures. The two opposite poles are differentiated as animal pole and vegetal pole. The imaginary axis passing through these two poles is called polar axis or animal-vegetal axis. It is the main axis of an egg. Polarity is usually expressed as a gradient in the ratio of cytoplasm and yolk from animal to vegetal pole. Polarity is responsible for the differentiation of egg as a bipolar structure.

So, the correct answer is option B.