Talk:XY sex-determination system

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Contents 1 I 2 Other sex determination systems 3 Evolution section 3.1 Evolutionary role of sex chromosomes 4 V Interesting 5 Swyer's 6 Discovery and etymology

[edit] I

I am not going to do any real writing today. Nonetheless, for this article we really need to remove some of the "Redirects". We need separate articles for this subject, as well as for the X Chromosome and the Y Chromosome. Much research exists on the genes found on these chromosomes, each of which can be the subject of an entire article. RK 22:24, Feb 13, 2005 (UTC)

I definately think that there should be independent articles for the X and the Y chromosomes (an probably all the other human chromosomes at some point), plus this article on the sex-determination system. Fixing all the redirects will be interesting :). The Y chromosome in particular has potential to become a featured article --nixie 22:38, 13 Feb 2005 (UTC)

Agreed, definitely scope for separate articles, although I think we should still include summaries and main article links in summary style in this article. I think the redirects have now been removed. --Lexor|Talk 23:48, Feb 14, 2005 (UTC)

!! I do not think XX males exists. The male cromosome must be present to get the testicle gene. On the other hand Y cromosome may not work correctly creating female or female like phenotype. !!

There are males with things other than XY. See XYY syndrome and Klinefelter's syndrome.

Yes there are indeed XX males. Just as an XY can develop as female due to defective SRY, so can residual SRY on an X chromosome cause a female to develop as male. I have read a lot of literature about this kind of thing... being an XY female and all. --86.147.1.63 (talk) 22:59, 14 December 2007 (UTC)

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I don't understand why the fruit fly is mentioned in this article, since it's not a mammal. AnonMoos 16:37, 14 January 2006 (UTC)

In Drosophila, males are XY, but sex is actually determined by the number of X chromosomes, so fruit flies are in the X-0 system. I'm going to add that, as well as the other systems. Kirbytime 17:20, 12 April 2006 (UTC)

You are wrong. In order to get a fertile male, most Drosophila species require the Y chromosome. As I recall, it is not part of the doublesex pathway, but genes on the Y are required for proper formation of the vas efferens.

[edit] Other sex determination systems

Should each one have a separate article, or should they all be merged into a single one? Currently, there are also these:

• X0 sex-determination system
• ZW sex-determination system
• Haplo-diploid sex-determination system

which were all made by me (or will be). Thoughts? Kirbytime 17:45, 12 April 2006 (UTC)

I guess it is about time to ask the question, "What do we mean by sex determination system?" Kribytime's classification of Drosophila as X0 is semi-valid if you are looking at mechanisms (dosage of X determines sex). However, Drosophila is an XY system -- normal females are XX; normal males are XY. While phenotypically classified as males, X0 flies are sterile (for the most part; there are some species where these males are fertile). My understanding was that this entry was simply on the gross chromosomal classification. For example, gingko trees would also fit in the XY system, although I have no idea how they use the X and Y specifically for sex determination. If we want this to be mechanisms, then it will take some serious rewriting. Ted 18:01, 12 April 2006 (UTC)

Ok, I think the confusion arose from the distinction between a fertile male and an infertile male. Yes, some X0 are infertile, but that genotype is still considered male, as opposed to female. Just like how humans with XXX genotypes are considered female (even though they might be infertile). Kirbytime 21:20, 12 April 2006 (UTC)

Sex determination system is a sequence of events that determine sex of a progeny. There are 3 levels in phylogenesis (during evolution of species and sex): gene (hermaphrodite forms use), chromosome (dioecious forms use) and genome (most advanced, bees use).

In ontogenesis (individual development) there are also 3 levels: genes, hormones and psychological. On each of the levels sex can actually be reversed. Default or base sex is female. Male sex is a derivative or variation.Sashag 18:10, 12 August 2007 (UTC)

[edit] Evolution section

At present this is an entirely fantastic set of claims referenced to obscure journals. This needs many more high-quality sources if it is to be included. Extrordinary clims require extrordinary sources. Tim Vickers 16:12, 4 August 2007 (UTC)

[edit] Evolutionary role of sex chromosomes

Sex differentiation provides for testing evolutionary innovations in the male genome before they are transferred to the female one. This is possible with dichronous (asynchronous) evolution, when evolution in males precedes that in females. ^[1] Hence, along with common autosomal genes for stable characters, exclusively male and exclusively female genes must exist. The male genes are already acquired by the male genome, but are not yet transferred to the female one. The female genes are already lost by the male genome, but still remain in the female genome. They constitute temporary evolutionary genotypic sexual dimorphism.

Autosomes are the most ancient chromosomes and contain the basic information for the species shared by both sexes. They play the role of the conservative memory of the dioecious genome and the depot for stable genes. Autosomes are mixed in each generation.

Sex chromosomes play the role of the operative memory or experimental genomic subsystem. They are aimed at changing the genome. Sex chromosomes are responsible for genotypic sexual dimorphism, they control and restrict the transfer of new information to the female genome.

The Y chromosome is the "conductor" of ecological information into the genome, the "place of birth" and testing of new genes and the accelerator and regulator of genotypic sexual dimorphism. By contrast, the X chromosome of the heterogametic sex provides the transportation of new genes from the Y chromosome to autosomes. This chromosome stabilizes, relaxes, and suppresses genotypic sexual dimorphism and accumulates genes that will be eliminated.

The concept sheds light on many problems: the chromosomal localization of genes and their transfer to other chromosomes, X-inactivation, mobile genes, mutation bursts, insertional mutagenesis, the association of the Y chromosome with stress, retroviruses, etc. In particular, it explains why and where genes "jump," why transpositions of mobile elements depend on ecological stress, and why different genes mutate simultaneously. ^{[2] [3]}

[edit] V Interesting

Just dropping in a reflist. V. interesting. Sounds like a plausible theory, but too neat and sweeping to have been confirmed and achieved consensus yet. It could be an example I've rather hoped would happen here at Wiki. Research scientists could popularize technical material here for us, before the establishment authorizes it, or the popular media broadcast it. I'm not suggesting this as an aim for Wiki, just a realistic expectation, given the vast ammount of research and sufficient time.

In this particular case, I suspect the papers are theoretical papers, i.e. they present an explanation of evidence, not the only explanation. Alastair Haines 06:08, 8 October 2007 (UTC)

[edit] Swyer's

I have a condition called Swyer syndrome, which as you can see has an extensive article. It is 46,XY sex-reversal due to SRY defects/deletions. Do you think it is related enough to this page to mention?--86.147.1.63 (talk) 22:59, 14 December 2007 (UTC)

You could add the link in "See also". Tim Vickers (talk) 23:18, 14 December 2007 (UTC)

[edit] Discovery and etymology

This article needs some information about the discovery of this mechanism and about the etymology: why were the names X and Y chosen, and by whom? Shinobu (talk) 16:00, 25 May 2008 (UTC)