Oogenesis

[garytse86]

What do the polar bodies formed in oogenesis do?

[Jikx]

Here's useful website - http://distance.stcc.edu/AandP/AP/AP2pages/reprod/oogenesi.htm

Apparently, it does nothing. Its just a by-product of the asymetric cytokinesis of the oocyte, giving one very very big ovum, and a tiny polar body. Makes sense I guess!

[garytse86]

thanks a lot that makes sense, but surely such an useless production (the polar bodies) would be eliminated during the course of evolution!?

[FZ+]

There are no certainties in evolution. Wait a few million years and see...

[aychamo]

Aye, if they aren't hindering reproduction, there is nothing really selecting against them. Gary, I presume you are a male. What do your nipples do?

[Monique]

The first polar body is formed, because the oocyte needs to get rid of 23 chromosomes that were produced during mitosis, and thus goes through the first asymmetrical meiotic devision.

The second polar body is formed when the primary oocyte has to get rid of the duplicated chromosome that is still attached to the original chromosome, so it goes through the second asymmetrical meiotic division.

The meiotic divisions are asymmetrical, since the embryo-to-be, needs as many nutrients as it can get (the egg is the largest cell in the body).

So the polar bodies definately have a function, to take out the excess of genetic material with the least loss of nutrients.

The following image shows what actually is happening with the chromosomes
http://users.rcn.com/jkimball.ma.ultranet/BiologyPages/O/oogenesis.gif

[garytse86]

Aye, if they aren't hindering reproduction, there is nothing really selecting against them. Gary, I presume you are a male. What do your nipples do?

Yes I am a male :cool:






And thanks a lot Monique, it was difficult to find the uses of the polar bodies
:biggrin: