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edit·history·watch·refresh Stock post message.svg To-do list for Aneuploidy:
needs references
needs images - added a normal karyotype, maybe could use an example of abnormal karyotype

Needs total rewrite. Even the first sentence is ambiguous to an intelligent non-scientist and any rational interpretation raises more questions than it answers. Also the whole thing needs to be written in PLAIN ENGLISH not technical jargon and the technical words put afterwards in brackets. This is a term which any adult concerned about Down's Syndrome might come to. Yet it is written as for science graduates. Hopefully fixed? Medical geneticist (talk) 17:59, 16 August 2008 (UTC)

Priority 4


There is little more than a dicdef here; I propose moving the Haploidy, Diploidy, Haploidisation, Polyploidy, and Aneuploidy pages to Ploidy. You have to read all those articles to understand ploidy anywho. I'll be happy to do the merge after approvial. Lefty 16:02, 2005 Mar 12 (UTC)

also Haplodiploidy. Lefty 16:09, 2005 Mar 12 (UTC)

I've heard tetraploidy can be almost as common as diploidy in some plants. Should this be addressed (ie- state that ploidy is relavent only when talking about a specific species. Or is ploidy definded as "natural is diploidy.") DavidMendoza 22:14, 9 Apr 2005 (UTC)

  • Check out the ploidy artcile it is discussed there, but could probably use a bit more expansion. Even though tetraploidy is widely common in plants it is still considered polyploidy, it's our human diploid bias :) --nixie 00:28, 10 Apr 2005 (UTC)

recent findings suggest that aneuploidy may be more common[edit]

More specifically, in brains, perhaps in human brains.

--Extremophile 23:29, 5 September 2006 (UTC)

Discussion added. Medical geneticist (talk) 15:59, 6 October 2008 (UTC)

Conflicting Information[edit]

It says on this page that trisomy 16 is the most common trisomy in humans. The trisomy 18 page, however, says that it is the second most common trisomy after Down Syndrome (trisomy 21).

Trisomy 16 is the most common at conception, but the fetuses spontaneously abort. Trisomy 21 is the most common in live births, followed by trisomy 18, with 16 way down the list because it's almost always very lethal.

Discussion fixed. Medical geneticist (talk) 16:01, 6 October 2008 (UTC)

I'm not an expert on using Wikipedia, nor am I an expert on this material, so I can't do it myself, but I wanted to add to this header since it talks about Trisomy 16. In the Aneuploidy article, Trisomy 16 is marked as always lethal in the chart in the "Types" section. However, the linked article to Trisomy 16 says with Trisomy 16 mosaicism, it is possible, albeit highly rare, for live births to occur. Can anyone double-check? A Cynical Asian (talk) 07:13, 10 January 2016 (UTC)

Yes, that's accurate. If only some of the cells have an extra chromosome 16, the proportion of the cells that are affected correlates with the severity of the symptoms. If all cells are affected, the condition is lethal before birth and the red colour in the table is appropriate. Sminthopsis84 (talk) 14:45, 10 January 2016 (UTC)


This article (and the articles on cancer and carcinogenesis) does not appear to discuss the possible causal role of somatic cell aneuploidy in cancer. There's increasing speculation that a key step in the development of full-blown cancer is a chromosomal abnormality in a somatic cell, particularly if it produces chromosomal instability. It is noteworthy that every one of the heritable chromosomal instability disorders linked from that article is associated with elevated cancer risk and cancer in youth. —The preceding unsigned comment was added by (talk) 22:46, 28 April 2007 (UTC).

Discussion added. Medical geneticist (talk) 16:05, 6 October 2008 (UTC)

Trisomy 23[edit]

Panda, please address the arguments I've provided. Regarding your assertion about the non-existence of reliable sources in this otherwise unsourced article, see e.g. :

Avb 17:42, 11 December 2007 (UTC)

Per Wikipedia's verifiability policy:

Editors should provide a reliable source for ... any material that is challenged or is likely to be challenged, or it may be removed.

The term "trisomy 23" is not used in the medical literature.
A PubMed search on "trisomy 23" returns 0 results.
Most of the 23 results resulting from a Google Scholar search on "trisomy 23" are coincidental juxtapositions of the word "trisomy" and the number "23", a couple of others appear to be typographical errors where "trisomy 23" was mistakenly substituted for "trisomy 21".
The top 10 results of a Google search on "trisomy 23" are these unreliable sources:
  1. an unsourced GeoCities personal webpage of Doyline High School biology teacher Jim Williams.
  2. an anonymous unsourced genetics science webpage on the Plano Independent School District Secondary Schools website.
  3. an anonymous unsourced genetics science webpage on the Plano Independent School District Secondary Schools website.
  4. a wrong answer to one of Medtext Medical World, Inc.'s multiple-choice Pediatric Board Review Practice Questions 2005.
  5. a 2003 post by "Peez" to an "Internet Infidels Discussion Board (IIDB) Philosophical Forums / Evolution/Creation" forum thread.
  6. a typo in a 2007 post by "turtlensue" to her "Democratic Discuss / Topic Forums / Health" forum thread.
  7. an unsourced title on an anonymous library webpage of genetic disorder links on the Barrington High School website.
  8. a 2005 post by "RFXCrunner" to the "" forum thread "Michelle Wie Either really an XYX male or an XXY female?"
  9. an unsourced PowerPoint slide 62 for Unit 5 of Oklahoma City Community College biology professor Roger Choate's Bio 1314.
  10. a typo in a 2006 post by "mbilyeu" in a Columbus DSM Forums / DSM Lounge / Readers Rides forum thread "90 fwd talon."
Panda411 (talk) 21:48, 11 December 2007 (UTC)

I work in clinical genetics, and I have never heard the term trisomy 23. I don't think this should be used.Kxw1 (talk) 19:38, 19 December 2007 (UTC)

Sorry for the late response, completely slipped my mind. Kxw1, thanks for your response. I've never used the term myself. I've seen it used, though. I'm arguing that people who use it should find the correct article/section. If the term is incorrect, it might be helpful to say so in the article, if warranted by the number of people using it.
Panda411, thanks for the extensive reply. Please note that I did not propose a PubMed search, as trisomy of sex chromosomes itself is rarely discussed, unlike the three syndromes subsumed under it. It is true that a PubMed search for "trisomy 23" yields zero results. However, this also applies to a search for the description currently used in the article. PMID 10415146 is a V RS sources that supports the latter -- found using this external Google search.
I did not propose a Google search due to the high proportion of false positives. Nevertheless, I would not be surprised if the search contained informative V RS sources. It certainly illustrates that e.g. prospective parents returning home from genetic counseling with extremely distressing information, can and will use the term "trisomy 23" when looking for information on the Internet. As noted by you, a substantial number of these people are actually referring to trisomy 21/Down Syndrome; chances are that they will realize their mistake when arriving here. Also note that the pediatric board review practice question has an explanation below the answer that, I believe, illustrates my point.
It is true that the Google Scholar search I proposed above yields false positives. However, it also contains true hits, such as this one.
I'm not saying "trisomy 23" denotes a specific syndrome (it doesn't). The article currently uses an umbrella term for the various sex-chromosome trisomies. Other such terms include "gonosomal trisomy" and "sex-chromosomal trisomy". All of these terms are rarely used in the relevant scientific (medical, biological) literature. All I'm saying is that the same applies to "trisomy 23". I would not use it myself but some do.
Once again, my main concern here is how the encyclopedia will serve people who are looking up "trisomy 23". They're currently redirected here without any explanation. I'd like to give them a bit more. You have already deleted my first compromise. Here it is again, followed by two more:
  • "...trisomy of sex chromosomes (sometimes called trisomy 23)"
  • "...trisomy of the sex chromosomes (sometimes incorrectly called trisomy 23)"
  • "...trisomy of the sex chromosomes (chromosome pair 23)".
Please let me know what you think. Avb 18:29, 20 December 2007 (UTC)

Deletions are not considered aneuploidy[edit]

I don't think that Cri du Chat and 1p36 deletion should be in this article. Aneuploidy is defined as "having or being a chromosome number that is not an exact multiple of the usually haploid number" ( Deletions are not numerical but structural changes. While they can result in "partial monosomy", they are not generally thought of as aneuploid. I think these should be moved to a separate article on structural chromosome changes or chromosome microdeletions, if one exists.Kxw1 (talk) 19:43, 19 December 2007 (UTC)

See the Deletion (genetics) article. Avb 18:39, 20 December 2007 (UTC)
I added a small section on "Partial aneuploidy" to make this distinction. Medical geneticist (talk) 16:36, 6 October 2008 (UTC)

Other organisms?[edit]

This is a pretty good treatment of aneuploidy in humans, but that's a very limited view of the topic. I'd like to work on getting some information on other species in here. For now, perhaps the best way to do this without disrupting the organization of the page is to simply add a section on "aneuploidy in other organisms"? Agathman (talk) 17:51, 26 May 2009 (UTC)

I think there's been some expansion of this in the ploidy article. Not sure if you mean something different. Are there pathogenic situations with aneuploidy in other species? --- Medical geneticist (talk) 23:35, 26 May 2009 (UTC)
Yes, and not only pathogenic ones. Many plant species produce aneuploids with relatively little loss of viability, for instance. Aneuploids have a long history of use in genetic research in plants, as a means of locating genes on chromosomes. Inheritance of a gene on a monosomic or trisomic chromosome is different from the inheritance of genes on the normal disomics, so you can tell what genes are on what chromosome. The technique was used extensively in cotton and corn, among others, and contributed to the genetic maps that are now used in assembling genomic sequence data. For that matter, much of what we know about aneuploidy came originally from studies on Datura (Jimson weed). As for animals, Down syndrome is known in chimps -- it's trisomy of the homolog of human chromosome 21, and I imagine there are other examples -- my expertise is more in plants. Agathman (talk) 00:41, 27 May 2009 (UTC)

Multiple sex chromosomes; polyploidy[edit]

It's always been my understanding that multiple sex chromosomes (especially multiple X's) causes mental/cognitive underdevelopment. Has anyone any idea why this might be? Chbse 12:37, 19 June 2010 (UTC) —Preceding unsigned comment added by Chbse (talkcontribs)

The process of X-inactivation is thought to be the mechanism for dosage compensation between males and females. However, there are genes such as those in the pseudoautosomal region that escape X-inactivation (and are thus expressed twice as much in females than in males). The current theory is that overexpression of these genes might be involved in the developmental delay sometimes seen in individuals with multiple X chromosomes. In general, the more X chromosomes present, the more likely the individual will have cognitive impairment. However, it should be recognized that there could be significant ascertainment bias in that these conditions were first recognized in people who were institutionalized and therefore more severely affected. --- Medical geneticist (talk) 00:54, 19 July 2011 (UTC)

First sentence is now inaccurate[edit]

The first sentence of this page has been repeatedly changed to an inaccurate one by an editor who cites WP:NOTJOURNAL as their rationale. Please see Wikipedia_talk:What_Wikipedia_is_not#This_page_being_used_to_support_wikilawyering for further discussion. Sminthopsis84 (talk) 13:03, 24 April 2015 (UTC)

I like this version "is the presence in a cell of an atypical number of chromosomes" as it is simple and still true. Doc James (talk · contribs · email) 13:30, 24 April 2015 (UTC)
We could change atypical to abnormal to simplify further. Doc James (talk · contribs · email) 13:31, 24 April 2015 (UTC)
What is the nature of the dispute? It looks like one editor wants more precision and the other wants less jargon. If the problem is the word choice, then can the language be simplified while preserving the precision? If that is not the problem, then what is the concern? Blue Rasberry (talk) 13:33, 24 April 2015 (UTC)
User:Blue Rasberry, my definition is accurate, as WP:RS defines it. I got it from Science magazine, which I cited, and Science is as authoritative a WP:RS as you can get. I also thought of using the NEJM definition, of "normal," which is equally authoritiative, and which is basically what User:Doc James suggested. But in matters of sexuality, I don't want to prescribe what is "normal."
(Campbell's Biology calls it an "aberration.")
I don't think there's a conflict between being easy to understand and being precise. Science and NEJM do both every week.
For reference, here's my version:
Aneuploidy is the presence in a cell of an atypical number of chromosomes.
I don't think this introduction is more accurate:
Aneuploidy is a condition in which the number of chromosomes in the nucleus of a cell is not an exact multiple of the monoploid number of a particular species,[citation omitted] such as when there is an extra chromosome or one missing.
At McGraw-Hill, we had scientists (including me) who started out writing like that, and we had editors who would strike it out and show us how to write in simple English.
They told me that if your reader can't understand your opening sentence, he's not going to read the rest of it, and if your reader doesn't read it, what's the point of writing?
I read Science and NEJM every week, and I couldn't figure it out the first time I read it.
This would be a good example for a writing course.
As I explained in the edit box, you can't define a word in terms of other words that your readers don't understand. If they don't know what "aneuploid" means, they're unlikely to know what "monoploid" means.
And providing a link for the unfamiliar word is no excuse. Every professional editor I know agrees that you can't do that. You have to include everything in the work itself that your reader needs for a basic understanding of your point. That's why I was glad to see that Wikipedia agreed in WP:NOTJOURNAL.
I hope I didn't drive User:Sminthopsis84 off Wikipedia. Most people don't enjoy having their writing changed. I don't usually enjoy it myself. But an ordinary reader has to understand a Wikipedia article -- at least the introduction. --Nbauman (talk) 09:59, 25 April 2015 (UTC)

To explain further, since the policy talk entry has become bogged down in discussing the content here, here are the two versions of the first sentence (or two) of the page:

  • The current version: "Aneuploidy is the presence in a cell of an atypical number of chromosomes." (followed by a citation where someone made that statement)
  • The previous version: "Aneuploidy is a condition in which the number of chromosomes in the nucleus of a cell is not an exact multiple of the monoploid number of a particular species,[a citation is here] such as when there is an extra chromosome or one missing. It differs from polyploidy, which involves full multiples of the monoploid number."

The presence and lack of links are as in the originals.

  • First another opinion on what aneuploidy is, from Dorland's Medical Dictionary (sorry, mine's a bit old, the 28th edition): "any deviation from an exact multiple of the haploid number of chromosomes whether fewer (hypoploidy, as in Turner's syndrome) or more (hyperploidy, as in Down's syndrome)." It's a wonderful dictionary, but has the small problem that it deals with human medicine, and so can relax its use of the term "haploid". When, as in wikipedia, polyploid organisms such as wheat are also discussed, it is necessary to distinguish between haploid and monoploid (otherwise we could never discuss the important wheat breeding experiments with the B chromosomes from rye, and much more).
  • There are two common topics that I believe a reader might think are aneuploidy but they are not. Atypical chromosome numbers for a group of organisms, such as polyploid species in a genus or polyploid individuals in a plant species (even all humans, because their chromosome number is not typical for the great apes), and endopolyploidy such as in the salivary glands of insects.
  • The wikipedia policy states "can be understood by any literate reader of Wikipedia without any knowledge in the given field before advancing to more detailed explanations of the topic". Okay, I see that the original sentence was difficult for "any literate reader", but the new version is misleading, and I maintain that being misleading is worse, that the readability should not be achieved by butchering content.
    • What is a literate reader? Because this topic has some relevance to medicine, I believe that a large subset of the literate readers we should expect to come here are people who know something of the Greek roots of medical terms. They would look at the word and see that it breaks down as an-eu-ploidy, meaning not-good/normal-ploidy. Looking up ploidy, the first sentence is "Ploidy is the number of sets of chromosomes in a cell." The reader would logically, I believe, conclude that aneuploidy means an abnormal number of sets of chromosomes in a cell, but that is wrong. Sminthopsis84 (talk) 14:03, 25 April 2015 (UTC)
    • This group of literate readers might then compare their interpretation of the word itself to the first sentence on the page:
Aneuploidy is the presence in a cell of an atypical number of chromosomes.
So which is it, is it an atypical number of chromosomes, or an atypical number of sets of chromosomes? I believe they would give up on wikipedia at that point and go to a library. They might go to wiktionary, which has "The condition of being aneuploid; the state of possessing a chromosome number that is not an exact multiple of the haploid number of the organism in question." that's not bad, though it has the loose usage noted above of "haploid".
  • The policy also states "While wikilinks should be provided for advanced terms and concepts in that field, articles should be written on the assumption that the reader will not or cannot follow these links, instead attempting to infer their meaning from the text." I disagree that knowing what monoploid means without clicking the link should be essential to understanding, though I agree that if someone doesn't know what aneuploid means then they are unlikely to know what monoploid means. However, it is not necessary to know what monoploid means to see that it is a number, and that multiples of that number are involved in polyploidy, and aneuploid does not involve multiples of that number. In other words, it is perfectly possible to gain an understanding of aneuploidy without following the link.
  • It would not be helpful to substitute "haploid" for "monoploid" because they are not the same thing in many organisms (they are the same only in diploids, such as humans). For a triploid, monoploid=x and haploid=1.5x, for a pentaploid, monoploid=x and haploid=2.5x, etc.
  • The use of the citation to support the new sentence is problematic, it is citing someone who wrote a simple sentence as if that is necessarily all that can ever be said on the topic. It is as if "The maple is a tree." is the end of the matter, the reader should assume that the spruce tree they are looking at must be a maple. Sminthopsis84 (talk) 14:58, 25 April 2015 (UTC)
Are we sure that polyploidy is not a subtype of aneuploidy? I would try to look but internet is not good enough right now Doc James (talk · contribs · email) 07:37, 26 April 2015 (UTC)
Yes, we are sure that polyploidy is not a subtype of aneuploidy, because in fact "euploidy" is the term for having chromosomes that are an integral multiple of the monoploid number, and aneuploidy means not that. In order to sort out the mess that has crept in online with all sorts of supposedly introductory course material, it is necessary to look in quite serious reference works. A good one that weighs less than one of the modern massive textbooks (those cover DNA-sequence information, transcription and translation, etc., as well as the older light-microscopy of chromosomes) is Rieger, Rigomar; Michaelis, Arnd and Green, Melvin M. 1968. A glossary of genetics and cytogenetics: Classical and molecular. Springer-Verlag, New York. isbn:9780387076683. Sminthopsis84 (talk) 11:56, 26 April 2015 (UTC)
If sources state slightly different things, these should be explored in the main body of the article, and the lead provide a summary that doesn't exclude anything pertinent. If there are several sources, the lead should not just quote or paraphrase one (as is currently the case). In fact as I understand it, per the MOS, there shouldn't be any citations in the lead - they should all be in the main body. PaleCloudedWhite (talk) 08:09, 26 April 2015 (UTC)

Okay found refs now that I have internet. "Ananeuploid is an individual organism whose chromosome number differs from the wild type by part of a chromosome set." [1] Doc James (talk · contribs · email) 15:44, 26 April 2015 (UTC)

Okay clarified it without making it complicated.
Yes the lead should have citations. It does not NEED citation but there is nothing wrong with it having them Doc James (talk · contribs · email) 15:54, 26 April 2015 (UTC)
"Aneuploidy is the presence in a cell of an abnormal number of chromosomes other than extra complete set of chromosomes."
I don't understand that. What does it mean? Is that a complete sentence? --Nbauman (talk) 06:25, 27 April 2015 (UTC)

Have clarified. We have "Aneuploidy is the presence in a cell of an abnormal number of chromosomes" with this being the exception to that rule "with the exception of a difference of one or more complete sets of chromosomes" Doc James (talk · contribs · email) 14:37, 27 April 2015 (UTC)

  • Coming to this now, it's still far from clear. Agree nbaumann; more explanation & more refs are what are usually needed - this isn't Twitter. Johnbod (talk) 20:16, 28 April 2015 (UTC)
[2] --Ozzie10aaaa (talk) 20:30, 28 April 2015 (UTC)
'Fraid not - the tricky bit is "... with the exception of a difference of[clarification needed] one or more complete sets of chromosomes." I'vew poked about a bit, but I'm rather out of my depth. Apart from the missing word, your ""Aneuploidy is the presence in a cell of an abnormal number of chromosomes other than AN extra complete set of chromosomes." is a better start, & Ozzie's Bond (just above) seems usefully full & clear. Someone else needs to add though. Johnbod (talk) 20:34, 28 April 2015 (UTC)

──────────────────────────────────────────────────────────────────────────────────────────────────── It might be better to use multiple short sentences:

Aneuploidy is the presence of an abnormal number of chromosomes in a cell, such as having 45 or 47 chromosomes in a cell when 46 is expected. It does not include having one or more complete sets of chromosomes, which is usually called polyploidy. An extra or missing chromosome is a common cause of genetic disorders, including some human birth defects. Some cancer cells also have abnormal numbers of chromosomes.

It's too complicated if you try to cram all of that into a single sentence. WhatamIdoing (talk) 00:19, 29 April 2015 (UTC)

Going the right way! The lead is very short now, so lots of room. Personally I'd be inclined to give Downs as an example in the lead. Johnbod (talk) 00:55, 29 April 2015 (UTC)
Yes both those are really good. Will add Doc James (talk · contribs · email) 10:42, 29 April 2015 (UTC)

Assessment comment[edit]

The comment(s) below were originally left at Talk:Aneuploidy/Comments, and are posted here for posterity. Following several discussions in past years, these subpages are now deprecated. The comments may be irrelevant or outdated; if so, please feel free to remove this section.

Rated "high" because "trisomy" redirects here and is highschool/SAT biology content. - tameeria 03:01, 29 April 2007 (UTC)

Last edited at 03:01, 29 April 2007 (UTC). Substituted at 07:47, 29 April 2016 (UTC)

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