Saturday, December 27, 2008

spermless development?

I have been sitting here in front of my computer thinking of something to write about cells. Somehow, after writing about the egg cell and the sperm cell, I cannot think of anything else to talk about. Of course there is still so much more to discover about cells. I have not even talked about the energy-generating centers in cells yet – meaning the mitochondria and chloroplasts. However, I don’t feel like starting their stories today. Not just yet anyway. So what cell story should I tell today?

Okay, here’s one – do you know that egg cells can start the first stages of development even without the sperm cells? Yes they can!

The first stage of development after fertilization is what is called as cleavage. This simply involves the rapid cell division of the fertilized egg. Experiments have shown than even a pin-prick can trigger this initial stage. However, after dividing several times, the egg cell will stop dividing and will not proceed to the next stage of development which is called gastrulation.

So later stages of development need the combined information coming from both the egg cell and sperm cell but the initial stage of development does not need the information from the sperm cell. Isn’t this amazing?

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