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Embryonic Development: Cleavage
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What is true for cleavage : -Cleavage is the series of rapid mitotic divisions of the zygote that form a multicellular embryo (morula and then blastula).
There is no growth between the divisions (the interphase is very short), so the overall size of the embryo remains about the same as that of the zygote.
As the same volume is divided into more and more cells (blastomeres), each cell becomes smaller.
So during cleavage the size of the cells decreases. -
Cleavage in mammals :The mammalian (human) egg is alecithal (has very little yolk), so the cleavage furrows divide the whole egg completely. This is holoblastic cleavage.
The blastomeres formed are nearly equal in size, so it is described as holoblastic and nearly equal (in detail, slightly unequal and rotational).
Discoidal cleavage occurs in the yolky eggs of birds and reptiles, and superficial cleavage in insects.
So, as per the answer key, cleavage in mammals is holoblastic equal.