CBSE Class 10 Answered

Depending mostly on the amount of yolk in the egg, the cleavage can be holoblastic (total or entire cleavage) or meroblastic (partial cleavage). The mammalian eggs are isolecithal i.e. with a small even distribution of yolk. Embryos formed from such eggs show holoblastic cleavage. This is a major pattern of embryonic cell divison in which cytokinesis completely separates cells during division. As a result, the blastomeres are completely separated. Here, the entire egg participates in cell division.