Talk:Sex-determination system

Untitled
The definition in the first paragraph is not very clear. From the definition, one could conclude that a sex-determination system is a method that, when applied to a certain individual, tells you whether that individual is a male or a female. In that sense, a sex-determination system for dogs would be "look if you can find testicles". AxelBoldt

Removed buck-billed from platipuses: platipuses are always duck-billed as there is only one species galf

I believe this reference for duck-billed platipuses, may have come about as the research done on platipuses XY genes was primarly concerning evolution. Hence at once stage the platipuses have had more one species - over time.

A bit on UBE1 and mole voles, from an article on the shrinking Y chromosome, Natural History, September 2002. Vicki Rosenzweig

Redirection
Gonosome redirects here, but this article doesn't even mention the term, much less define it! --91.63.214.210 (talk) 19:40, 10 January 2008 (UTC)

Fish, Amphibians
The article seems a bit sketchy. From a Maths book I see a reference to a 'reverse' xy system in Birds, Fish & Amphibians, however correct that is; presumably it's a reference to what is called the wz system, the article only refers specifically to birds & insects. It would be interesting to know a bit more categorically what different species' systems are.

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I have read information to the effect that the WW:WZ system for birds AND snakes, (i'm not sure about insects) is a reverse xy system in that as the articles says two of the same chromosomes are needed for male determination, instead of the XX style in human.

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I've always heard it discussed as ZW .. rather than WZ. Anyone else?

I have heard of it as the ZW system. And this way makes more sense to me, because it is the first letter that is the base. Just like how the genotypes of the different sexes of humans are XX and XY (where the first letter of both is the same), the genotypes of, say, chickens, are ZZ and ZW (The Z is analogous to the X, because it alone does not signify a gender, whereas the presence of a W chromosome or a Y chromosome does). Kirbytime 00:01, 13 April 2006 (UTC)

DAX1, Female genes
New research has shown that human females and males come about between a interation of a few genes, and importantly the gene DAX1 if expressed on the X ovum in large amounts can actually cause female development. In any case, female genes in the sex-determination system need to be worked into this article.

Lists of Organisms
It wouldn't hurt to create an explicit list of the organsims belonging to each reproductive system, perhaps in their own, separate page. "Some insects" (as part of the WZ system) is a bit vague

--Weenie

I've created articles on the different kinds
I'm linking this article to them, and vice versa:


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

This is going to turn out great, I know it =) Kirbytime 23:40, 12 April 2006 (UTC)

Uhoh, I have hit a sort of roadblock... ploidy versus Haplo-diploid sex-determination system. Merge them, or what? Kirbytime 23:51, 12 April 2006 (UTC)

In the News -- Parthenogenic Komodo Lizards
A komodo dragon producing offspring by parthenogenesis at a London zoo is in the news currently. Press reports describe that the offspring must be male.

Please add specifications for Komodo dragons to the article (and the Komodo Dragon article as needed) explaining this female producing males situation.


 * DonePhorofor (talk) 19:54, 9 January 2012 (UTC)

Unexpected -- Should Be Explained -- Cross Order Differences/Similarities
What is so striking about this subject is that different systems occur within the same types of animals (for example insects) and that common systems occur across vastly different animal classes.

This is so at odds with what would be expected for descent from common ancestors that it should be specifically pointed out and discussed in a section dedicated to the question. That is, discussed from the point of view of parallel evolution, and the unexpected volatility rather than stability of sex selection systems. (Why isn't there one standard system for all vertibrates for example -- as there is one standard bone structure system?)

From the article currently we might get the impression that the very same genes are being used in these divers species for sex determination -- I suspect it is only the conceptual system that is the same and the actual genes are different. This should be clarified.

More on the relationship of the different actual genes -- to the degree known -- in the different orders (as is currently discussed for birds vs. mammals) would clarify this issue.

No mention of sex hormones!!
I don't think this artikle is very clarifying. Sex is determined by the sex hormones, oestrogens on the one hand an testosteron on the other hand. In a sensitive phase the indifferent gonads of the embryo (or adult clown fish) will produce either male or female hormones. When this process starts the hormone production will follow a positive feedback loop. The hormone producing cells will produce still more of the hormone and this will influence other factors as the morfology of the germ cells. When the development has a male pathway "Anti Mullerian Duct Factor" will be produced which will eliminate the formation of the Mullerian duct (uterus and ovarian duct).

The sex chromosomes will play a part in the first formation of male or female hormones in the primordial gonad in a manner that is still unclear. The basic formation and determination of gender is however a hormonal affair.

Some fish for instance can be sex reversed when treated a few weeks after the hatching of the eggs with synthetic hormones. This will result in for instance fish which are genetically female (XX) but will function as males. When these fish fertilize a normal female, all female offspring (XX) will result as the XX constitution of the offspring will predetermine them as females.

The temperature effect with crocodiles can be explained in the same manner. Viridiflavus 13:46, 24 February 2007 (UTC)

I reverted the most recent edit because, while there may be a better way to start the article, removing the common mammal XY system altogether is not it. Vicki Rosenzweig (talk) 16:25, 9 October 2009 (UTC)

99.92.194.248 (talk) 15:13, 7 November 2012 (UTC)Gender is not a hormonal affair, as it is a social construct. Are you talking about sex?

What about others?
What about XXY, XYY in humans? —Preceding unsigned comment added by 46.70.66.76 (talk) 07:33, 16 May 2011 (UTC)

Mammals aren't reptiles
"All sex chromosomes started out as an original autosome of an original reptile that relied upon temperature to determine the sex of offspring. After the mammals separated..." - but mammals aren't reptiles! (may be it should mention amphibians?)Rnnsh (talk) 17:31, 30 May 2012 (UTC)

I think if you mean this, for example, giraffe has 62 chromosomes so female giraffe is 60+ZW while male is 60+ZZ? Line 8 the Pink (talk) 06:43, 25 August 2015 (UTC)

The subject of the article.
I suspect I understand your problem; but decided that the talk page might be a better place to answer than in the article history comments. (If nothing else, there are less space limitations here.)

As I suppose you realised, when you reread the paragraph mentioning hermaphrodites, that statement does not at all refer to humans. There are some other organisms, where some or all individuals have two sexes, and actually all may be both fathers and mothers of offspring. This has nothing to do with "differently normal" sexual orientation of some humans; and if you read the sentence carefully, you should see that it does not.

So, there was no problem with the use of "hermaphrodite" in that sentence. However, there could be a problem when a rather experienced Wp editor misunderstands the scope of the article; not due to this minor edit of short duration, but because this indicates that a number of less experienced readers also might misunderstand it. The real problem might be, that a number of medical, human oriented articles are interwoven with a number of general biological articles (and found in the same navboxes and categories. E. g., this article is listed in Template:Sex determination and differentiation, where most articles are general biological, buth others, like Development of the reproductive system, only referring to human physiology.  Comparing that article with this one, neither of them indicate their scopes clearly in the titles or the first sentences; you have to read a bit into the articles to understand whether they concern only ourselves, or living organisms in general.

Thus, Flyer22, I think that your mistake is all too easy to understand. I also think that this mixture and cross-referencing of "human scope" and "general biology" articles is reasonable and well motivated. After all, biologically, humans are animals, and share features (and problems) with a lot of other kinds of animals (and even with other organisms). However, if I'm right, we really should care more about making the scope of each such article explicitly clear in its beginning; e. g., by opening this article
 * " In biology, a sex-determination system is..."

and the other article
 * "The development of the reproductive system in human anatomy is..."

or in some similar manner; and doing the same in a whole bunch of these articles. (Suggested additions are underlined.)

There are some articles which start with general biology, but then rapidly restricts the scope. In these cases, I think the best solution is to end the general section with an explicit statement of the kind
 * "In the rest of the article, we only treat ... in humans."

Of course, later someone migt wish to extend e. g. Development of the reproductive system to cover other organisms as well. This should be perfectly feasible; but the editor then also should rephrase the opening of the article to reflect the newer, broader scope.

What do you think? JoergenB (talk) 18:20, 15 April 2015 (UTC)


 * JoergenB, this edit by me (followup edit here) was not a mistake. I understood that the sentence was stating "Most sexual organisms have two sexes. Occasionally, there are hermaphrodites in place of one or both sexes." I addressed the topic of intersex people by changing the text to "Most sexual organisms have two sexes. Occasionally, there are hermaphroditic organisms or intersex people." I don't consider intersex people a third sex. I made the change because this article is not just about non-human organisms (it is a general article that relates to non-humans and humans), and I wanted the lead to be clear that not only do atypical sex chromosomes occur in humans, but, when they do, it is not precise to refer to humans as hermaphrodites; it is more precise to call them intersex. Furthermore, using the term hermaphrodite to refer to some non-human organisms has even been criticized. I don't hugely oppose use of the term hermaphrodite to refer to non-human organisms, however. Also, you stated, "that statement does not at all refer to humans," while W.andrea stated, "Not sure why the mention of humans when the paragraph's subject is all organisms." In other words, "all organisms" includes humans. And I don't see why you brought up sexual orientation; that is a completely different topic. That stated, I am not interested in having you change the lead back to how I formatted it.


 * On a side note: I'm not sure if it was your intention, but your above post sounds condescending. And there is no need to WP:Ping me to this talk page since this article/talk page is on my WP:Watchlist. Flyer22 (talk) 18:49, 15 April 2015 (UTC)
 * I apologise if I sounded condescending; I'll try not to. (Perhaps this is a bad effect of being a teacher.)  On the other hand, I had no way to know that this article is on your watchlist, until you told me.
 * I also apologise for bringing "sexual orientation" into the discussion. I now have checked up the terminology, and see that the (biological) intersex treats in humans should not be confused with either the sexual orientation or the social expressions of gender (or of what in a given cultural context might be considered as gender-related habits and behaviour).  My mistake.
 * However, the main point still stands. The term "hermaphrodite" here refers to organisms which may both be fathers and mothers to offspring.  Among humans, this would necessiate the presence of both functional ovary tissue and functional testicle tissue.  This condition has never been documented as naturally occurring in humans, according to either Intersex or True hermaphroditism; although there have been a very few cases with both kinds of tissues present from birth, and eventually one of them operational.  On the other hand, intersex conditions are much more widespread.
 * Therfore, it would be absolutely misleading to deskribe intersex individuals from Homo sapiens as the human correspondence to individuals from other species, which produce both operating ova and operating sperms.
 * To quote our article Hermaphrodite:
 * Historically, the term hermaphrodite has also been used to describe ambiguous genitalia and gonadal mosaicism in individuals of gonochoristic species, especially human beings. The word intersex has come into preferred usage for humans, since the word hermaphrodite is considered to be misleading and stigmatizing, as well as "scientifically specious and clinically problematic".
 * One of the references even would like to go one step further, and replace "intersex" with references to DSD, "disorder of sex development". However, the hermaphroditism in slugs, tunicates et cetera that our article covers are no disorders, but (within these groups of organisms) perfectly normal.
 * If we would claim that 'intersexual humans are the human variant of the 'true hermaphrodites' the article treats, we would just aggravate the misunderstandings. You then would state that a disorder of sex development in a human is on par with the normal development of both functional ova and functional testicles in slugs, where ordinarily in mating each individual both transfers sperms to the other indindual, and receives sperms therefrom, and both individuals thus get fertilised eggs.  Thus, where people both in medicine and biology (and our articles) have tried to explain that the two phenomena "intersexual development" and "hermaphroditism" are not at all the same thing, the changes you suggest would perpetuate exactly the prejudiced idea that "intersexual" just should be a pleonasm for "hermaphroditical", and thus work in exactly the opposite direction of what you intended.
 * I hope that this was clear enough, and not too condescendingly expressed... Best regards, JoergenB (talk) 08:09, 23 April 2015 (UTC)


 * I'm not fully sure what you are trying to get across, so I'll end this discussion by stating that I know what I am talking about when it comes to sex and gender/sexology matters, and that I know what I intended with the edit I made in this case. Flyer22 (talk) 08:14, 23 April 2015 (UTC)
 * Yes, there may be too much misunderstanding here to make further discussion fruitful right now. (And I indeed believe that you know much more than I do about sex and gender among humans.) Best regards, JoergenB (talk) 08:28, 23 April 2015 (UTC)


 * Hey Flyer22, I'll try to be a bit more concise than JoergenB. Hermaphroditisim, strictly speaking, means presenting both male and female parts in full. European earthworms, for example, have two fully functional sets of reproductive organs- one male, one female. When they mate they exchange sperm in both directions, giving and receiving. Meanwhile, in humans (and other animals), being intersex means being neither fully male nor fully female, but somewhere in the middle. I'm aware that this condition used to be called hermaphroditism and that it is now considered an incorrect and sometimes rude term for it. I can sort of see how the sentence in question in the article could be misconstrued, but given that the article for hermaphrodite explains the controversy, I don't think it's necessary to change anything.
 * I apologize if I'm saying anything that was said already, because I didn't read everything JoergenB wrote.
 * W.andrea (talk) 01:30, 7 May 2015 (UTC)


 * Yes, W.andrea, I know all of that concerning the topic of hermaphrodite and intersex. And no need to apologize. Flyer22 (talk) 08:23, 7 May 2015 (UTC)

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Assessment comment
Substituted at 05:50, 30 April 2016 (UTC)

plants? - change title
It's a fairly good article. But given the title, it should cover the entire tree of life, including e.g. plants. Or rather, the title should be changed to ANIMAL Sex-determination system. — Preceding unsigned comment added by Hhbruun (talk • contribs)
 * We go by WP:Common name. Flyer22 Reborn (talk) 23:01, 31 October 2018 (UTC)

If intersex/mutations are mentioned in the beginning of the article, perhaps there should be a section describing the possible DSDs that can result in human sex determination (lack of SRY function, XO, etc.). Kking1110 (talk) 19:33, 8 February 2019 (UTC)

There are zero sources in the lead
I don’t see any sources cited in the lead. CycoMa (talk) 23:54, 12 October 2020 (UTC)

Moving stuff
I’m moving stuff from sex over to here.CycoMa (talk) 02:48, 3 August 2021 (UTC)

XY sex determination needs trimming
The part on XY sex determination needs some trimming it is honestly a little too long to be honest.CycoMa (talk) 20:11, 25 August 2021 (UTC)

Environmental factors / genetic factors
Would heterostyly fit in one of these headings? Some plants, as well as the male / female system, also have physical differences differentiating each sex into classes which can only breed with each other - pin males can only fertilise thrum females and vice-versa, and at least some species seem to have genetic factors making homostylous matches infertile. I don't have the background in botany to write this up properly, though, or to fit in in the right place - any takers? Philculmer (talk) 16:30, 20 October 2023 (UTC)


 * white throated sparrows do something very similar, I came on here to mention that because it's pretty neat JustAnotherCatLover... (talk) 15:20, 23 November 2023 (UTC)