Another noteworthy trait of monotremes involves their developmental characteristics, such as the zygotic development of platypuses : Most mammal zygotes go through holoblastic cleavage, meaning that following fertilization, the ovum is split due to cell divisions into multiple, divisible daughter cells.
12.
The cell division in the embryo is radial ( cells form in stacks of rings directly above each other ), holoblastic ( cells are separate, although adjoining ) and regulative ( the type of tissue into which a cell develops is controlled by interactions between adjacent cells, rather than rigidly within each cell ).
13.
In the absence of a large concentration of yolk, four major cleavage types can be observed in isolecithal cells ( cells with a small even distribution of yolk ) or in mesolecithal cells ( moderate amount of yolk in a gradient ) "'bilateral "'holoblastic, "'radial "'holoblastic, "'rotational "'holoblastic, and "'spiral "'holoblastic, cleavage.
14.
In the absence of a large concentration of yolk, four major cleavage types can be observed in isolecithal cells ( cells with a small even distribution of yolk ) or in mesolecithal cells ( moderate amount of yolk in a gradient ) "'bilateral "'holoblastic, "'radial "'holoblastic, "'rotational "'holoblastic, and "'spiral "'holoblastic, cleavage.
15.
In the absence of a large concentration of yolk, four major cleavage types can be observed in isolecithal cells ( cells with a small even distribution of yolk ) or in mesolecithal cells ( moderate amount of yolk in a gradient ) "'bilateral "'holoblastic, "'radial "'holoblastic, "'rotational "'holoblastic, and "'spiral "'holoblastic, cleavage.
16.
In the absence of a large concentration of yolk, four major cleavage types can be observed in isolecithal cells ( cells with a small even distribution of yolk ) or in mesolecithal cells ( moderate amount of yolk in a gradient ) "'bilateral "'holoblastic, "'radial "'holoblastic, "'rotational "'holoblastic, and "'spiral "'holoblastic, cleavage.
