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The haploid spores fall from the sporophyte and germinate by mitosis, given the right conditions, into the gametophyte stage, the prothallus. (I, a layman, quote.) But isn't mitosis exactly the separation of two sets of chromosomes into two haploids? Aren't we talking about fertilisation here into a gametophyte stage, or else the spores are still sporophytic at first. —Preceding unsigned comment added by 81.152.7.211 (talk) 09:07, 22 May 2008 (UTC)
- No meiosis is the reduction division that creates haploid cells from diploid cells. All that mitosis does is to duplicate the existince chromosomes, regardless of whether the cell is haploid or diploid. Meiosis produces the spores, but that is the only point in a typical plant life cycle where meiosis occurs. --EncycloPetey (talk) 13:34, 22 May 2008 (UTC)
Is the "Advantages of alternation of generations" really necessary in this article? Shouldn't it belong in the A. of G. article itself? --24.68.62.185 (talk) 05:32, 22 August 2008 (UTC)
- It's also wrong, as stated. Not all alleles are necessarily expressed at the gametophyte stage. — Preceding unsigned comment added by 88.110.115.27 (talk) 08:59, 19 November 2011 (UTC)
- Yes, and not all "genes" occur in just one copy. I've adjusted it a bit. I've also removed the "expand section" tag which had the following comment
reason=recent results comparing genetic control in Chlamydomonas to land plants show that there was gene duplication before the sporophyte became significant|date=September 2013
- I'd argue that gene duplication is a separate issue. Other work by S. Otto, one of the authors on the citation that I've just added, shows that among Angiosperms there have been many cycles of doubling followed by trimming the genome, resulting in gene duplication. Chlamydomonas has diploid and haploid phases, and its ancestors could be expected to have similarly undergone gene duplication. Sminthopsis84 (talk) 14:14, 10 October 2015 (UTC)
- Yes, and not all "genes" occur in just one copy. I've adjusted it a bit. I've also removed the "expand section" tag which had the following comment
Title edit
Google ngrams show that "prothallus" has been more common than "prothallium" since about 1911. "Prothallus" gets more than twice as many Google hits than "prothallium". Most of the wikilinks to the article are via the redirect "prothallus". So it seems clear to me that the title should be "prothallus" based on WP:AT, and I have moved it. Peter coxhead (talk) 12:48, 17 February 2020 (UTC)
- When applying some fixes for the move, I found that actually "prothallus" was used more in the article than "prothallium", increasing the justification for the move. Peter coxhead (talk) 12:52, 17 February 2020 (UTC)