Talk:Y chromosome

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This article could use a cleanup

Things that should go in the Y chromosome article:

• Development of understanding y-linked traits (1950s), list of Y linked traits, other disorerd arising from multipe Y chromosomed
• Y chromosome as a degenerate X chromosome (1960s)
• SRY, sex determining gene
• mapping and sequencing the Y chromosome, number of genes on Y
• Most of the Y chromosome doesn't recombine, 95% of the Y chromosome is in the non-recombining region (male specific region) vs pseudoautosomal regions where crossing occurs. Implications for Y chromosome degeneration - losing the Y chromosome (see Prof. Jenny Graves, Bryan Sykes (ick)), evidence that the Y chromosome is not going to be lost [1]
• Use of the Y chromosome in following the parental line through generations, the Thomas Jefferson-Sally Hemings research is a good case study

--nixie 23:26, 13 Feb 2005 (UTC)

The sentence:

"The chromosome may be used to trace sexes have unpaired X chromosomess; in the other, both females and males have XX."

in the opening paragraph does not seem to make sense, unfortunately I don't know enough about the topic to be able to change it. Perhaps someone more knowledgeable could make this sentence more clear.

Contents 1 Unpaired chromosome 2 Flawed and doomed? 2.1 Y chromosome gen map 3 XYY 4 Origins and Evolution section 5 How does this effect Y chromosome evolution?

[edit] Unpaired chromosome

From reading the article, it says that the Y chromosome is the only unpaired chromosome and thus can't repair normally. This makes sense, but what about the unpaired X chromosome in males? Wouldn't that suffer from being unable to recombine too? Scott Ritchie 07:31, 17 January 2006 (UTC)

Yes...if the X could never find another X. But every time a male sires a daughter (roughly half the time) he provides his X chromosome with a partner X to practice normal recombination like other autosomes. Since no woman can pass on a Y chromosome to viable offspring, the Y chromosome never meets a similar match. It becomes the loneliest chromosome. --ScottieB (talk) 01:44, 21 May 2008 (UTC)

[edit] Flawed and doomed?

I ran across an article in the New York Times, here's the link http://plaza.snu.ac.kr/~premed/The%20New%20York%20Times%20%20Science%20%20A%20Conversation%20With%20Bryan%20Sykes%20Is%20Genghis%20Khan%20an%20Ancestor%20Mr_%20DNA%20Knows.htm

Dr. Bryan Sykes, a human genetics professor at Oxford University, says that write the Y chromosome is flawed and doomed, and predicts that it will disappear in 120,000 years. I don't know much about genetics, but maybe some of you can shed some light on this and what other genetics professors think of Sykes theory.--Moosh88 22:16, 4 February 2006 (UTC)

There are two new popular science books out this year on Y, his and another (Jones I think). I think Sykes exaggerates a bit for popular literary effect, but I liked his Seven Daughters of Eve (which deserves an article). Someone here should volunteer to read both and synposize them here, don't you think? alteripse 23:13, 4 February 2006 (UTC)

Yes, I think an article should be written. So do you know if what Sykes says is true?--Moosh88 04:40, 6 February 2006 (UTC)

It is speculation. I am sure he has his basic facts right, but his extrapolation into the past is somewhat imaginative and into the future is pretty iffy. alteripse 05:07, 6 February 2006 (UTC)

From what I understand, most geneticists agree that the Y chromosome was probably larger in the past, and has shrunk through time. That might deserve mention in this article, although I hesitate to add it without having sources to back it up. I agree that Sykes' prediction that the Y chromosome will disappear entirely is pretty speculative. It's hard for me to imagine what selective pressures would favor a complete loss of the Y chromosome, and I can think of some pretty good reasons its total loss would be selected against. --Geoff 06:41, 16 April 2006 (UTC)

[2]

Read the bottom.

That means that many of the genes on the Y chromosome do occur as pairs. Page says members of these pairs appear to be swapping out or recombining with each other -- allowing the genes to repair themselves when they get damaged. Page says this helps explain why these genes have been able to persist despite millions of years of assault from random mutations. And, he says, it means the Y chromosome won't simply keep shrinking away until it disappears altogether.

--Vehgah 06:28, 20 April 2007 (UTC)

[edit] Y chromosome gen map

   N     bp beg     bp end   symbol
*..1.....132989.....160020..PLCXD1
*..2.....161426.....170887..GTPBP6
*..3.....168410.....168893..LOC645997
*..4.....214970.....267627..PPP2R3B
*..5.....505079.....540146..SHOX
*..6.....890456.....890836..LOC442442
*..7....1274894....1291527..CRLF2
*..8....1347701....1388827..CSF2RA
*..9....1415509....1461582..IL3RA
*.10....1465045....1470994..SLC25A6
*.11....1480936....1494314..CXYorf2
*.12....1482137....1531733..ASMTL
*.13....1541465....1616000..P2RY8
*.14....1670486....1681413..DXYS155E
*.15....1674348....1721974..ASMT
*.16....1687070....1689047..LOC646128
*.17....2147547....2428975..DHRSX
*.18....2414455....2429008..ZBED1
*.19....2537312....2566758..LOC646154
*.20....2546623....2566758..LOC646162
*.21....2619228....2669350..CD99
*.22....2680144....2703031..LOC646182
*.23....2714896....2715792..SRY
*.24....2717868....2718438..AYP1p1
*.25....2769623....2794997..RPS4Y1
*.26....2811137....2811693..LOC442479
*.27....2863546....2909891..ZFY
*.28....3166225....3166770..LOC646223
*.29....3221849....3222840..LOC646231
*.30....3477853....3478625..LOC360018
*.31....3507126....3508082..TGIF2LY
*.32....3610641....3612883..USP12P3
*.33....3792657....3794758..LOC359798
*.34....4729051....4730970..LOC359996
*.35....4928267....5670265..PCDH11Y
*.36....5134408....5136177..LOC359800
*.37....5265646....5267021..LOC359792
*.38....5501137....5502529..KRT18P10
*.39....5679332....5679472..LOC646283
*.40....5721289....5744414..LOC441533
*.41....5815551....5816781..LOC359794
*.42....6086838....6087873..LOC360014
*.43....6166628....6173312..LOC442480
*.44....6174264....6177053..TSPY2
*.45....6190045....6192364..LOC646303
*.46....6193247....6194003..LOC392583
*.47....6194588....6197320..TSPYP1
*.48....6232607....6232992..LOC392586
*.49....6256229....6271624..RBMY2GP
*.50....6377509....6385947..TTTY7
*.51....6399073....6401665..LOC646375
*.52....6793959....6802068..AMELY
*.53....6829174....6829508..LOC359997
*.54....6838727....7019724..TBL1Y
*.55....6839209....6839921..LOC646395
*.56....6878466....6878656..LOC360029
*.57....7028439....7034546..GPR143P
*.58....7127950....7128631..LOC646416
*.59....7202014....7309589..PRKY
*.60....7599509....7606019..RBMY2HP
*.61....7614843....7617634..TSPYP2
*.62....7618564....7618911..LOC646439
*.63....7627398....7629288..TTTY16
*.64....7641026....7704746..LOC360015
*.65....7732965....7738724..TTTY12
*.66....7762583....7763050..LOC646445
*.67....8055164....8072670..RBMY2JP
*.68....8105867....8107208..FAM8A7P
*.69....8131106....8131729..LOC646460
*.70....8192217....8207187..RBMY2KP
*.71....8445258....8461421..LOC646481
*.72....8611411....8611919..TTTY18
*.73....8632513....8633324..TTTY19
*.74....8711354....8745423..TTTY11
*.75....8832258....8844384..RBMY2MP
*.76....8854917....8866575..LOC140103
*.77....8962151....8968029..OFDYP3
*.78....9062832....9065636..CDY3P
*.79....9087248....9102222..LOC387359
*.80....9214670....9220483..RBMY1A3P
*.81....9227489....9232441..TTTY20
*.82....9235079....9237887..LOC653272
*.83....9250859....9253055..LOC642358
*.84....9255412....9258202..LOC653280
*.85....9271135....9273335..LOC642391
*.86....9275691....9278480..LOC653288
*.87....9291475....9293681..LOC642431
*.88....9296036....9298826..LOC653293
*.89....9906352....9911954..CYorf16
*.90....9914564....9917357..TSPY1
*.91....9930333....9932527..LOC642499
*.92....9934882....9937690..LOC653168
*.93....9950620....9952813..LOC642547
*.94....9955165....9957972..LOC653174
*.95....9970945....9973141..LOC642586
*.96....9975495....9978285..LOC653178
*.97....9995410...10004615..LOC642631
*.98...10058330...10062762..RBMY3AP
*.99...10138709...10141308..TTTY8
*100...10154439...10162865..LOC642695
*101...10165262...10168905..TTTY21
*102...10188193...10206085..TTTY2
*103...10200765...10221898..TTTY1
*104...10248762...10260854..TTTY22
*105...10278764...10283386..RBMY2NP
*106...10317273...10317781..LOC642796
*107...10353062...10355794..TSPYP3
*108...10358407...10359571..TTTY23
*109...10399155...10407451..RBMY2OP
*110...10422169...10422444..LOC642833
*111...10469825...10482899..RBMY2QP
*112...10514003...10516805..TSPYP5
*113...10603792...10604053..MRP63P10
*114...10644865...10646712..LOC359724
*115...11657566...11675221..LOC642953
*116...11700948...11830697..LOC653050
*117...11861367...11880320..LOC642974
*118...11930597...11930929..LOC643001
*119...11948007...11949275..LOC643034
*120...12011847...12013172..LOC643050
*121...12014764...12034529..LOC643055
*122...12041071...12084645..LOC643062
*123...12089190...12091907..LOC439957
*124...12411630...12412959..LOC643077
*125...12553014...12554542..ASSP6
*126...12587914...12619284..ADLICANP
*127...12875451...12882830..RPS24P1
*128...12883033...12895923..LOC643123
*129...12952316...12953992..FAM8A8P
*130...12962992...12978253..ARSEP
*131...12984769...13009211..ARSDP
*132...13028602...13043512..GYG2P
*133...13163003...13165165..APXLP
*134...13240312...13255727..LOC359791
*135...13283692...13313547..TTTY15
*136...13322554...13482162..USP9Y
*137...13422577...13425306..CDY4P
*138...13526171...13541784..DDX3Y
*139...13551159...13569486..CASKP
*140...13716183...13719029..SFPQP
*141...13732910...13796579..LOC643199
*142...13869657...14101944..UTY
*143...13907850...13908828..PSMA6P
*144...14324841...14327298..TMSB4Y
*145...14339339...14340111..LOC360022
*146...14371009...14373971..LOC643222
*147...14490157...14490340..KALP
*148...14607046...14607782..VCY1B
*149...14677492...14678234..VCY
*150...15145848...15464921..NLGN4Y
*151...15260347...15262587..LOC359793
*152...15529106...15529354..LOC643298
*153...15561963...15563023..CYCSP46
*154...15969943...16077360..HDHD1BP
*155...16172603...16173377..STSP
*156...17260877...17261257..LOC643409
*157...17805760...17815097..LOC643470
*158...18137870...18140705..LOC140004
*159...18196435...18200726..LOC401629
*160...18249687...18251066..TAF9P1
*161...18342471...18344469..CDY5P
*162...18351073...18365814..LOC442863
*163...18377471...18379572..ACTGP2
*164...18390254...18391834..XKRY
*165...18417459...18422092..SEDLP3
*166...18430473...18444108..OFDYP1
*167...18499534...18501493..CDY2B
*168...18503272...18505408..CDY6P
*169...18533870...18543004..LOC387360
*170...18572542...18574838..CDY7P
*171...18605523...18614661..LOC387361
*172...18643147...18645283..CDY8P
*173...18647061...18649020..CDY2A
*174...18701890...18718085..OFDYP2
*175...18726466...18731099..LOC414751
*176...18756623...18758403..XKRY2
*177...18769084...18770992..LOC414754
*178...18782638...18798325..LOC442864
*179...18804091...18806089..CDY9P
*180...18897554...18898769..TAF9P2
*181...18947807...18952104..LOC401630
*182...19007855...19010690..LOC349448
*183...19074324...19090533..OFDYP4
*184...19129086...19130882..XKRYP1
*185...19162168...19165506..USP9YP1
*186...19167962...19210237..HSFY1
*187...19202480...19211795..TTTY9B
*188...19203237...19250453..OFDYP5
*189...19275330...19277451..LOC392597
*190...19295001...19359714..OFDYP6
*191...19351156...19360471..TTTY9A
*192...19352714...19395009..HSFY2
*193...19397449...19400787..USP9YP2
*194...19432072...19433868..XKRYP2
*195...19469436...19488655..OFDYP7
*196...19493775...19499502..CYorf14
*197...19611914...19614093..CD24
*198...19694248...19698690..TTTY14
*199...19948772...19950038..LOC140028
*200...20076705...20124427..BCORL2
*201...20102304...20106136..LOC360000
*202...20188624...20211564..CYorf15A
*203...20213724...20225769..CYorf15B
*204...20326689...20366212..SMCY
*205...21036942...21090502..TTTY10
*206...21140964...21141838..SMCYP
*207...21146999...21164428..EIF1AY
*208...21181387...21183335..FAM8A9P
*209...21217129...21236432..LOC643956
*210...21298528...21314174..TBL1YP
*211...21328049...21352306..RPS4Y2P
*212...21380050...21384785..LOC643987
*213...21432653...21433815..LOC340623
*214...21473115...21478883..LOC360028
*215...21609569...21615992..LOC644005
*216...21792624...21793055..LOC359795
*217...21882435...21890709..RBMY2SP
*218...21966422...21972836..RBMY2EP
*219...22001598...22008621..RBMY2TP
*220...22039403...22042213..TSPYP4
*221...22064693...22073611..RBMY1H
*222...22082646...22097060..RBMY1B
*223...22106178...22120600..RBMY1A1
*224...22154874...22165940..TTTY13
*225...22207875...22210742..CDY10P
*226...22233100...22245385..LOC387364
*227...22267419...22270447..CDY11P
*228...22366922...22373747..OFDYP16
*229...22435611...22450021..RBMY1D
*230...22459153...22473562..RBMY1E
*231...22482650...22494774..RBMY2AP
*232...22527746...22561219..OFDYP8
*233...22620132...22621340..CDY12P
*234...22627291...22651542..PRY2
*235...22700522...22702369..TTTY6B
*236...22724077...22738477..RBMY1F
*237...22753857...22757412..RBMY2UP
*238...22852333...22854411..TTTY5
*239...22937101...22943631..RBMY2VP
*240...22959011...22973416..RBMY1J
*241...22995128...22996994..TTTY6
*242...23045932...23070172..PRY
*243...23076123...23077331..CDY13P
*244...23136242...23169718..OFDYP9
*245...23202691...23210753..RBMY2BP
*246...23281543...23284789..LOC386728
*247...23317859...23325425..RBMY2WP
*248...23407119...23408250..TTTY17
*249...23491990...23528819..TTTY4
*250...23539798...23561000..BPY2
*251...23605570...23606703..ZNF381P
*252...23684896...23754545..DAZ1
*253...23775010...23846885..DAZ2
*254...23934917...23948332..LOC360020
*255...24092437...24104566..RBMY2CP
*256...24137130...24170433..OFDYP10
*257...24229813...24231020..CDY14P
*258...24236875...24250216..LOC442865
*259...24271222...24273020..XKRYP3
*260...24310405...24321220..LOC414753
*261...24326358...24353785..OFDYP11
*262...24409806...24413047..CDY15P
*263...24417005...24418335..CDY16P
*264...24472231...24474029..XKRYP4
*265...24492262...24497157..TTTY3B
*266...24518566...24526332..LOC414752
*267...24538835...24550716..OFDYP12
*268...24600764...24603549..CDY1B
*269...24605312...24607448..CDY17P
*270...24659321...24662768..CDY18P
*271...24730081...24732997..LOC360024
*272...24738969...24742766..CSPG4LYP2
*273...24760999...24761604..LOC359998
*274...24765502...24770366..GOLGA2LY1
*275...24804013...24805395..LOC360025
*276...24832861...24836353..LOC360016
*277...24917471...24918013..LOC286570
*278...24951612...24959168..RBMY2XP
*279...25040867...25041998..TTTY17B
*280...25125737...25162560..TTTY4B
*281...25173539...25194742..BPY2B
*282...25235272...25240390..LOC392603
*283...25318610...25368908..DAZ3
*284...25389452...25462571..DAZ4
*285...25540738...25545902..LOC442486
*286...25586436...25607639..BPY2C
*287...25618618...25655427..TTTY4C
*288...25739178...25740308..TTTY17C
*289...25822015...25829580..RBMY2YP
*290...25863195...25863737..LOC286568
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*293...26010846...26015710..GOLGA2LY2
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*297...26118442...26121889..CDY19P
*298...26173753...26175889..CDY20P
*299...26177652...26180437..CDY1
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*301...26254864...26262630..SEDLP5
*302...26284025...26288923..TTTY3
*303...26307152...26308950..XKRYP5
*304...26362839...26364169..CDY21P
*305...26368127...26371368..CDY22P
*306...26427366...26443516..OFDYP14
*307...26459932...26470747..SEDLP4
*308...26508125...26509922..XKRYP6
*309...26530930...26544271..LOC442866
*310...26550126...26551333..CDY23P
*311...26625200...26644130..OFDYP15
*312...26677120...26689249..RBMY2DP
*313...26833358...26904213..PPP1R12BP
*314...26956489...26956765..CYCSP48
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*316...27150218...27190190..PARP4P
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*318...57509845...57524511..SPRY3
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*320...57623407...57685814..SYBL1
*321...57727405...57728306..LOC644970
*322...57739640...57752876..IL9R

There are 322 genes on Y chromosome.

[edit] XYY

I recommend deleting the last three sentences about the inaccurate and obsolete "criminal karyotype" concept in the paragraph about 47,XYY in the Chromosome-linked diseases section.

I agree that the concept is inaccurate and obsolete and that explaining how the concept arose and was subsequently disproved is important, but I do not think this can be done in three sentences and trying to do so introduces other inaccuracies and should not be part of an encyclopedia article about the Y chromosome.

It is inaccurate to generalize:

When chromosome surveys were first done in the 1960s, it was reported that a higher than expected number of men in prisons were found to have an extra Y chromosome.

It is incorrect to say:

Better population surveys have since demonstrated that the association was simply that boys and men with learning problems are more likely statistically to spend time in prison and that there is no other independent statistical association with extra Y.

In the mid-1960s, large, comprehensive chromosome surveys of British special hospitals for the mentally retarded found a higher than expected number of tall, mentally retarded XYY patients.

After this, several, much smaller, highly selected and biased studies of institutionalized, tall, mentally retarded men and boys in other countries found some with an XYY karyotype--including a very few in prison.

The only large, comprehensive, nationwide chromosome survey of institutionalized XYY males was done in Scotland in the mid-1960s and found that XYY men were not overrepresented in prison. Panda411 07:00, 9 July 2006 (UTC)

We can certainly change wording to improve accuracy, but I want to be sure I understand your dissatisfaction with the existing paragraph, which I originally wrote. Since there is an entire article on XYY syndrome I was trying to concisely confirm that

1. xyy is indeed the "criminal karyotype" that the reader vaguely remembers hearing about,
2. that the concept is erroneous and the association with criminal behavior false,
3. because it arose from an ascertainment bias in the first decade of kt research, and was probably found because of the somewhat higher rates of mental impairments of all kind in institutionalized males.

So I don't understand which of those concepts you disagree with, as your expanded version seems entirely consistent with my brief one. And since I had not even looked at the XYY syndrome article until right now, I note that it entirely lacks a discussion of this issue. If the association were entirely dead and remembered by no one, I would not try to resurrect it, but I regularly run into medical students or others who have some vague memory of hearing about a "criminal karyotype": if we dont acknowledge it, we can't refute it. Should we further shorten it to something like this "Most men with this syndrome have no distinguishing behavioral or body features, but within the group of XYY men there are more with learning problems than in the general population, and men with XYY are taller than average. An association of XYY with criminal behavior originally reported in the 1960s was erroneous." and put your fuller story in the xyy syndrome article? alteripse 12:40, 9 July 2006 (UTC)

I have both general and specific disagreements with the last three sentences of the current XYY paragraph and the proposed shorter alternative sentence:

General disagreements about discussing the false "criminal karyotype" concept in this article or the XYY article:

1. I think the first four sentences of the XYY paragraph that you originally wrote are an excellent summary of the condition and are perfect for this article about the Y chromosome, but I disagree with devoting most of the paragraph to discussing why decades-old misinformation about the condition is wrong. I think both the summary of the XYY condition in this article and the main XYY article should address what it is, not what it is not.
2. The best place for refuting misinformation about XYY would be in a separate article on the History of the XYY Syndrome, but writing such an article consise enough for an encyclopedia would be difficult since there is no good book or article in print or online that does this well.
3. Discussing something that was not and is not true can perpetuate it. For example, using several popular search engines to look up the phrase "criminal karyotype", all but two of the results came from this Wikipedia article. The other two results were: 1) a clinical scenario for a clinical genetics specialist about a patient finding decades-old misinformation on the internet about a "criminal karyotype", and 2) a high school essay by a 10th grade student quoting misinformation about a "criminal karyotype" from a 30-year-old book.

Specific disagreements regarding the current last three sentences:

1. The first chromosome surveys in the 1960s found a higher than expected number of tall, mildly mentally retarded XYY patients (not criminals) in the only four British special hospitals (not prisons).
   1. Most of the XYY patients had been institutionalized in a system (during its peak years) of mental handicap hospitals that has since been dismantled (there were scandals in the 1960s exposing horrible conditions in some underfunded hospitals). Most of the XYY patients had never committed a crime against a person. Many of the XYY patients were in the special (security) hospitals because they had frequently run away from non-security mental handicap hospitals where they had been institutionalized since childhood.
2. The first and only large and comprehensive survey of prisons was done in Scotland in the 1960s and did not find a higher than expected number of men in prisons to have an extra Y chromosome.
3. There have not since been better population surveys demonstrating that boys and men with an extra Y chromosome are statistically more likely to spend time in prison.
4. Referring to the "criminal karyotype" concept as "inaccurate and obsolete" could be misunderstood to suggest that it is merely outmoded or passé.

Specific disagreement regarding the proposed shorter alternative: "An association of XYY with criminal behavior originally reported in the 1960s was erroneous.":

This is not accurate since large population studies of 12 XYY men in Copenhagen in the 1970s and 17 XYY men in Edinburgh in the 1990s found they had higher lifetime criminal conviction rates (for minor property crimes), but that lower intelligence in the XYY men with convictions accounted for this. XXY and XY men with lower intelligence also have higher criminal conviction rates. Panda411 06:27, 10 July 2006 (UTC)

Ok, thanks for clarifying and supplying details-- I have no doubt your details are correct. I won't quibble with your wording objections and I don't feel strongly that we need to leave the "criminal karyotype" phrase in this article. Go ahead and change.

However, I do have a substantive disagreement with the bigger issue, which is whether we should even allude to and explain the urban legend about the "criminal karyotype" (call it CK for short) somewhere. So pretend we are having this same discussion on the XYY syndrome page because that is really where it should be. There are two arguments for dealing with it. First, I had heard of this CK business long before wikipedia existed and it has been known to be erroneous since the late 1970s if not sooner. Nevertheless it never dies, and I assume by now it is college and high school teachers who have been propagating it, because I still occasionally run into students or residents who have a vague memory of having heard that sometime long before. Maybe you are right and no one but me is keeping it alive, but I doubt it, which brings us to the second reason I disagree with you. The nature of wikipedia is such that if we remove it, someone will add it to one of the two articles within a year (maybe within a month) thinking they are being helpful and complete. I would rather acknowledge the folklore nature of it and refute it as you did above. The most parallel example I can think of is the ever-recurring rumors about which movie star has androgen insensitivity syndrome: the name changes but the rumor never dies, and I think it best to simply acknowledge it as folklore with a life of its own (and you can see in the article and on the talk page how I handled it). So please write up a brief summary for the XYY syndrome article so you have immunized it against more pernicious versions and we can remove it anywhere else it crops up. If you don't I probably will and you seem to know more details and care more about the exact wording. Thanks. alteripse 19:23, 10 July 2006 (UTC)

I am still concerned that an adequate refutation of the criminal karyotype concept would take up a disproportionate portion of the much shorter XYY syndrome article, devoting too much of the article to what the XYY syndrome is not. I think the most appropriate place to refute the criminal karyotype concept would be in a separate article on the History of the XYY syndrome discussing how misconceptions about it arose, leaving the XYY syndrome article to discuss what the XYY syndrome actually is. The short paragraph in the much longer androgen insensitivity syndrome article acknowledging and dismissing recurring false rumors is fine because the paragraph takes up less than 2% of the article text and there is nothing to support the rumors.

Although this Wikipedia article's inclusion of the phrase "criminal karyotype" may help keep that specific phraseology alive, I didn't mean to imply that that phrase, or you, or this article was what was keeping the unfair association of XYY with crime alive.

The reason you run into medical students and residents who associate XYY with crime is because some leading medical textbooks teach them that. An example of uneven progress:

The multi-author, two-volume, 3760-page, $279 hardcover Kaplan & Sadock's Comprehensive Textbook of Psychiatry, 8th ed. (2005) is the first edition in the 38 years since its first edition in 1967 that does not mention XYY.

Unfortunately, medical students and residents reading about Genetic Factors--Chromosomal Influences in Chapter 4.4 on Aggression in the lighter and more affordable 1460-page, $89 paperback Kaplan & Sadock's Synopsis of Psychiatry, 9th ed. (2003) are taught that:

Early studies indicated persons with the XYY syndrome could be characterized as likely to be apprehended and in prison for engaging in criminal behavior. Subsequent studies indicated that the XYY syndrome contributes to aggressive behavior in only a small percentage of cases. A famous case of an XYY insanity defense is illustrated in Figure 4.4-1.

Figure 4.4-1 is a large photo of a man who forty years ago this week committed one of the worst mass murders in American history. The caption gives his name, then explains that:

He was convicted in 1966 of slaying eight nurses in Chicago by stabbing and strangulation. His legal defense was based on his genetic makeup, which was XYY. Individuals with these genes have been reported to be tall, mentally retarded, have acne, and show aggressive behavior.

His legal defense was in fact not based on his genetic makeup which was never mentioned at any time during his trial or appeals. His karyotype was found to be 46,XY on two separate occasions (in 1966 before his pre-trial competency hearing and again in 1968 before his state appeal) by Dr. Eric Engel, a Swiss endocrinologist and geneticist then at Vanderbilt University studying sex chromosome abnormalities at whose request the studies were done confidentially for research. Detailed results were made public by the man's public defender at a news conference the day after he lost his state appeal in 1968. Dr. Engel published a photograph of the man's normal 46,XY karyotype in a scientific journal article in 1972. Mental retardation, acne, and aggressive behavior are not characteristic of XXY individuals.

The photo and caption first appeared in the Forensic Psychiatry chapter of the first edition of Kaplan & Sadock's Synopsis of Psychiatry in 1972 where it was merely one of five photos illustrating "a variety of cases in which mental illness was a legal issue." The photo and caption then disappeared for 31 years and 7 editions before returning to illustrate the 9th edition's chapter on Aggression in 2003. Panda411

Clearly you know more about the history of this than I do and your details are fascinating. I remember being told in medical school about 100 miles from Chicago in about 1973 that Richard Speck had an XYY kt but I don't even remember the context of the talk (psychiatry or genetics or something else). I have no reason to disbelieve your story that it had been refuted in a medical journal in 1972-- clearly the lecturer was not up to date or I remembered exactly the wrong version of the story. It seems to be very hard for teachers to relinquish a vividly illustrative story even when it turns out to be false. I am quite surprised to hear that any medical texts were still purveying the CK story after the 1980s because even we non-geneticists knew it was false by then. Go ahead and put all this into a separate history article then, but the XYY syndrome article will need a link and a sentence saying the CK story is false. I have a bit of sympathy with your desire to simply ignore it but too much experience at wikipedia to think some version won't be put back in within weeks or months. alteripse 11:47, 13 July 2006 (UTC)

[edit] Origins and Evolution section

The following sentence appears to make no sense: "However, recombination between the X and Y chromosome was harmful because it provided males without needed male genes or females with unneeded male genes." --Xyzzyplugh 18:10, 10 August 2006 (UTC)

It seems meaningless to me also. Anyone have any idea what was intended? alteripse 19:46, 10 August 2006 (UTC)

Under Human Y chromosome, I see the reference to '78 genes' (ref is not cited) while earlier under 'origins' I saw reference to '86 working genes' in the human Y chromosome (this does cite a reference). One of these must be wrong.

Indeed. In fact, the X chromosome article says:

The X chromosome contains about 2000[2] genes compared to the Y chromosome containing 78[3] genes, out of the estimated 20,000 to 25,000 total genes in the human genome. Giridhar (talk) 08:43, 14 May 2008 (UTC)

I have a concern about the Shrinking segment, specifically the first paragraph. I understand how a harmful mutation could not be removed via recombination, but wouldn't that make its bearer less likely to survive and/or reproduce, thus lowering the mutation's frequency in the population? This is the normal case for most deleterious mutations: those that receive are doomed to fail to pass them on. It seems unlikely a species would merely endure until a fortunate coding change or massive deletion wiped out the mutation. I am not an expert, so I am asking for either clarification of the theory or an appropriate reference.--ScottieB (talk) 01:50, 21 May 2008 (UTC)

[edit] How does this effect Y chromosome evolution?

This was written in the development of Y chromosome - Gene conversion section:

This recombination phenomenon RecLOH is also observed in Genetic Genealogy when multicopy Y-STR markers located at adjacent palindromic arms change from different repeat counts to twin alleles of equal length. Often 2, 3 or more Y-STR markers are involved in the same recombinational event and change to twin alleles at once.

How does this affect the development of the chromosome? That's what the section tries to explain, and is not a dump of trivia. So what makes this not a trivia in this case? Mikael Häggström 17:32, 31 July 2007 (UTC)