Researchers at the Marine Biological Laboratory (MBL) visualized the very beginning of this cellular rearrangement of the egg after fertilization.

“The most interesting and mysterious part of developmental biology is the origin of the body axis in animals,” said study co-author Tomomi Tani.

The results of her work showed that both parents contribute to the body position of their offspring. New research raises fundamental questions in developmental biology.

The prevailing theory for the location of the body axis was that the actin filaments within the ovum, which are involved in cell movement and contraction, set in motion the rearrangement of cytoplasmic material after fertilization. But seeing this happen was a challenge. The fact is that the beginning of the process occurs quickly and at very small distances inside living cells.

To overcome these obstacles, the scientists used a fluorescence polarizing microscope. It allows you to display events taking place at distances measured in nanometers. This is a thousand times smaller than the diameter of a human hair.

When polarized, light waves partially or completely oscillate in only one direction: up / down, left / right, clockwise / counterclockwise, and so on. This is why the filter allows polarized light to pass through in one orientation but blocks it out when rotated.