What is "cytoplasmic determinant"

n. (context biology English) A substance, present in an egg or blastomere, that determines the fate of those cells that inherit it during cleavage.

Cytoplasmic determinants are special molecules which play a very important role during oocyte maturation, in the female's ovary. During this period of time, some regions of the cytoplasm accumulate some of these cytoplasmic determinants, whose distribution is thus very heterogenic. They play a major role in the development of the embryo's organs. Each type of cell is determined by a particular determinant or group of determinants. Thus, all the organs of the future embryo are distributed and operating well thanks to the right position of the cytoplasmic determinants. The action of the determinants on the blastomeres is one of the most important ones. During the segmentation, cytoplasmic determinants are distributed among the blastomeres, at different times depending on the specie and on the type of determinant. Therefore, the daughter cells resulting from the first divisions are totipotent : they can, independently, lead to a complete individual. That is not possible after the cytoplasmic determinants have been distributed in the differentiated blastomeres.