Talk:Meiosis

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rated top as high school/SAT biology content - tameeria 14:48, 17 February 2007 (UTC)

The article would benefit from having pictures of the meiotic stages, e.g. prophase I stages. It needs a section on chromosome crossover and meiotic recombination. - tameeria 18:48, 18 February 2007 (UTC)

pachytene stage - During this stage the paired chromosomes "thicken" and crossing over occurs - from lecture notes. I would like to learn more about each of these stages. Please do research on these -ene stages and fill in more details, maybe make a stub.


Contents

[edit] Regarding major revision 21:36 & 21:42 on 26 July 2005

I've revised At birth?

Meiosis is arrested in Prophase I prenatally for mammalian females. It stays in Prophase I until ovulation, when the oocytes are formed -- completing the rest of the meiotic stages.Ted 19:13, 25 January 2006 (UTC)

[edit] Site of discovery

The article currently claims that meiosis was discovered in sea urchin eggs. Surely sea urchin gonads or sea urchin embryos are meant, no? I checked the article on Oskar Hertwig but this discovery is not mentioned there. --arkuat (talk) 05:07, 23 March 2006 (UTC)

Wasn't Hertwig reporting pronuclear fusion during sea urchin fertilization, not meiosis? Dr d12 01:06, 28 February 2007 (UTC)

That's indeed what the Hertwig article indicates now, but this article still (mysteriously) credits him with discovering meiosis. --arkuat (talk) 21:26, 21 February 2008 (UTC)

Oskar Hertwig now fills out the details thus: he recognized the role of the cell nucleus during inheritance and chromosome reduction during meiosis arkuat (talk) 11:35, 13 June 2008 (UTC)

[edit] Detailed description of meiosis

Dies someone have some pictures to accompany the detailed explanation of meiosis? I think it would greatly increase its understandability.Redmess 19:35, 7 May 2006 (UTC)

[edit] pictures or diagrams

I think this page needs diagrams at each step of meiosis in order to help the reader visulize the process. I don't think the one diagram at the beginning is enough. as said above.

[edit] suggestion of diagram

here is one you can add: http://www.ncbi.nlm.nih.gov/About/primer/images/Meosis4.GIF but i'm having troube including it.

and another better one: http://www.bioethics.gov/images/sc_images/meiosis.gif

I definately think we should use the second one, the picture on the page is much too confusing. Eipiplus1 11:17, 11 December 2006 (UTC)

[edit] tetrad

I thank you guys for having the word tetrad in this article. I've been wanting to know what in the world that word had to do with meiosis. Okay, I think that's all. --JDitto 06:51, 10 October 2006 (UTC)

[edit] Terminology

The simpler, but less descriptive names for the two parts of meiosis are (obviously) Meiosis I and Meiosis II. More descriptive names are reduction division and equational division, respectively. The diagram at the top of the article alternatively uses "reductional division" to name the first step. Yet these more descriptive names are mentioned nowhere in the text of the article. —Gordon P. Hemsley→✉ 23:35, 12 November 2006 (UTC)

[edit] Latest developments

I removed this statement from the prophase I section:

During this stage, one percent of DNA that wasn't replicated during S phase is replicated. The significance of this cleanup act is unclear.

While I doubt that it is untrue, it was not cited, and if anything, it would confuse the reader. If someone can find the journal article it came from, I feel as though it could be added in a different section (possibly about the latest developments; we could also add something about how experiments on [[S. cerevisiae]] show that a lot of the processes of crossing over might occur before currently thought or become visible). I just feel that adding these special cases to the body of information might be confusing. If someone wants to work with me to add such info, I'd be willing to add it. --Michael 01:31, 5 February 2007 (UTC)

[edit] All Eukaryotes?

Meiosis is essential for sexual reproduction and therefore occurs in all eukaryotes

I thought there were Eukaryotes that reproduced entirely asexually? For example, the page on Amoebae says "Amoebas reproduce through binary fission", ie, Mitosis, and the page Amoebozoa puts them in the Eukaryotes... Evercat 03:07, 15 July 2007 (UTC)

Ah think it was just a missing comma.... anyway I've added parentheses to make it clearer... Evercat 03:12, 15 July 2007 (UTC)

[edit] sentence chopped

The last sentence of the first paragraph (referencing meiospores) is arbitrarily specific for the introduction to an encyclopedia article. It is also a non sequitur. That information does not go there, if we are interested in prioritizing and readability. If you wrote it, find another spot for it. I am editing it.

[edit] Minor Revision on Polar Bodies

I corrected this statement: "Each oogonia that initiates meiosis will divide twice to form a single oocyte and two polar bodies." There are actually three polar bodies produced by meiosis in females, as one cell devides into two, and two cells divide into four, not three. and if only one viable oocyte is produced, that leaves three nonviable polar bodies. —Preceding unsigned comment added by 75.68.115.0 (talk) 22:25, 8 February 2008 (UTC)


[edit] 1N vs 2N during meiosis

I've noticed repeated changes between 1N and 2N in the description of the first meiotic division. I'm changing it back to 1N (haploid) and refer you to the following:

  • If N refers to the number of chromosomes, 2N is diploid and 1N is haploid. Since all somatic cells have 46 chromosomes or 23 homologous pairs (one paternal and one maternal), somatic cells are diploid (2N). Likewise, spermatogonia are also diploid (2N). At the end of the first meiotic division, the secondary spermatocytes have 23 double-stranded (containing a pair of daughter chromatids) unpaired chromosomes and are, therefore, haploid (1N). At the end of the second meiotic division, there are 23 single-stranded chromosomes and these are also considered haploid (1N). (from http://www.andrologysociety.com/resources/handbook/ch.6.asp)

Note that N should not refer to the amount of DNA in a cell (as in part B in the above page) - instead, 'C' should be used for DNA content. Dr d12 (talk) 14:23, 7 May 2008 (UTC)

[edit] Edit on Diplotene stage

59.88.141.4 Thank you for your edit. I have tidied it a little. I hope you don’t mind. Prim Ethics (talk) 11:40, 19 May 2008 (UTC)

[edit] Why two divisions?

Why does the cell undergo two divisions? Wouldn't it be more likely to evolve as the cell splits once?

My ASCII diagram isnt working. Okay, verbal description. The cell has a chromosome pair. It doesnt double. It splits. Wouldnt that make two gamates?