厨房水槽堵塞:哈利波特和隐性等位基因

刚看了《哈利波特7上》，无聊的在PubMed里面用"Harry Potter"做关键词搜索文献，得到32篇文献，居然还有发在Nature上的文章两篇 还有其他牛文若干篇。灰常的欢乐。

附该文章链接： http://www.ncbi.nlm.nih.gov/pubmed/16094345

以免大家以为是我胡诌。最近真是闲的蛋疼。

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在下面第一篇nature文章中，在2005年《哈里波特与混血王子》出版后，来自澳大利亚皇家儿童医院的Graig等人，同样对哈里波特中描述的有超能力的巫师wizards and  witches与麻瓜muggle结合后，后代属性问题提出讨论:
巫师可以是来自各种种族，可以是巫师与巫女的后代，也可以是两个普通人（麻瓜）的后代，或者是混血的后代“half-blood”.
如果巫术这种超能力是孟德尔遗传的话，他们认为有证据表明超能力的W基因相对普通人的麻瓜基因M来说是隐性的（recessive allele）。那么巫师的两个等位基因应该是WW，麻瓜应该是MM, 混血的应该就是WM.
作者举出的例子是哈里的两个朋友罗恩·韦斯莱(Ron Weasley) 和纳威·隆巴顿（Neville Longbottom）以及他们的死对头德拉科·马尔福（Draco Malfoy）都是巫师和巫女的后代（WW X WW), 而赫敏（Herminone）是麻瓜生的女巫 （WW X WM）
作者还提到了其他几个遗传学上的概念：“不完全外显”（incomplete penetrance）：比如纳威·隆巴顿巫术就很烂，虽然是纯正的巫师家庭；"突变"(mutation):比如Filch虽然出身魔法世家，但是没有 魔法，有可能是他的魔法基因突变，而失去能力。

    Nature 436, 776 (11 August 2005) | doi:10.1038/436776a;                         Published online 10 August 2005
Harry Potter and the recessive alleleJeffrey M. Craig1,3,                          Renee Dow2                         MaryAnne Aitken2,3

• Chromosome Research, Murdoch Childrens  Research Institute, Royal Childrens Hospital, Flemington Road,  Parkville, Victoria 3052, Australia
• Genetics Education,  Murdoch Childrens Research Institute, Royal Childrens Hospital,  Flemington Road, Parkville, Victoria 3052, Australia
• Department  of Paediatrics, University of Melbourne, Royal Childrens Hospital,  Flemington Road, Parkville, Victoria 3052, Australia

We  are bombarded with news of genetic discoveries on an almost daily  basis, but people without a formal knowledge of heredity and genetics  can have difficulty in deciphering and applying this information.  Education and debate across all ages would undoubtedly help, but how can  we teach children these concepts
We believe that  successful lessons for younger children can be achieved using analogies  of direct interest and relevance. Most children are familiar with J. K.  Rowling's stories about the young wizard Harry Potter (whose latest  exploit, Harry Potter and the Half-Blood Prince, was published by  Bloomsbury in July). They are set in a world like our own, but  populated by a minority of people with supernatural powers (wizards and  witches) and a majority of people without (muggles).
Wizards  or witches can be of any race, and may be the offspring of a wizard and  a witch, the offspring of two muggles ('muggle-born'), or of mixed  ancestry ('half-blood').

            With the use of these examples, the concepts of mendelian genetics can be introduced to children as young as five.
    J. M Craig, R. Dow, M. A. Aitken

    This  suggests that wizarding ability is inherited in a mendelian fashion,  with the wizard allele (W) being recessive to the muggle allele (M). According to this hypothesis, all wizards and witches therefore have two  copies of the wizard allele (WW). Harry's friends Ron Weasley and  Neville Longbottom and his arch-enemy Draco Malfoy are 'pure-blood'  wizards: WW with WW ancestors for generations back. Harry's friend  Hermione is a powerful muggle-born witch (WW with WM parents). Their  classmate Seamus is a half-blood wizard, the son of a witch and a muggle  (WW with one WW and one WM parent). Harry (WW with WW parents) is not  considered a pure-blood, as his mother was muggle-born.
There  may even be examples of incomplete penetrance (Neville has poor  wizarding skills) and possible mutations or questionable paternity:  Filch, the caretaker, is a 'squib', someone born into a wizarding family  but with no wizarding powers of their own.
We  believe that, with the use of these examples, the concepts of mendelian  genetics can be introduced to children as young as five, and then built  on by gradually introducing specific terms such as 'gene' and 'allele',  and relating these to chromosomes and DNA. At every stage, the  children's familiarity with the Harry Potter characters can be used as a  hook to engage them in discussing concepts of heredity and genetics.


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对于这个问题，来自剑桥大学的Dodd等人则认为上一篇文章的分析论证不充分，因为没有证据表明超能力来自可遗传的性状，一个反例就是Hermione（赫敏）的父母均是麻瓜牙医，而且家族历史上没有人是有超能力的巫师。
“不完全外显”（incomplete penetrance）不能解释纳威·隆巴顿巫术超烂的巫术能力。在不完全外显中，个体的性状要么体现，要么不体现，不会出现一个中间状态。不良的巫术能力可能是不同的个体对对同一等位基因的可变表达（varivariable expressivity）.

    Nature 437, 318 (15 September 2005) | doi:10.1038/437318d;                         Published online 14 September 2005
Harry Potter and the prisoner of presumptionAntony N. Dodd1,                          Carlos T. Hotta1 &                         Michael J. Gardner1

• Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EA, UK

Jeffrey Craig and colleagues, in Correspondence ("Harry Potter and the recessive allele" Nature 436, 776; 2005),  recommend the use of analogies as tools for introducing young people to  scientific concepts. Taking their example from J. K. Rowling's stories  about the young wizard Harry Potter, they suggest that wizarding is a  monogenic trait, with the wizard allele (W) recessive to the muggle  allele (M). We believe the assumption that wizarding has a genetic basis  to be deterministic and unsupported by available evidence
Following  Craig and colleagues' analogy, Hermione, as a muggle-born witch, must  have WM parents. However, as Rowling fans could point out, Hermione's  parents were muggle dentists who lack any family history of wizarding.  It's true, of course, that chance may not have thrown up a witch or  wizard for many generations, or that any who did have magical powers may  have kept them secret to avoid a witch hunt.
What  about Neville's apparently poor wizarding skills? These cannot be  explained by incomplete penetrance, as Craig and colleagues suggest. In  incomplete penetrance, individuals either display the trait or not: they  do not display an intermediate degree of the trait. Poor wizarding  skills might be indicative of variable expressivity of an allele.  However, both variable expressivity and incomplete penetrance are  associated with dominant alleles. If the wizarding allele were dominant,  rather than recessive as suggested, wizarding children such as Hermione  could not be born to non-wizarding parents.
Neville's  clumsiness may, perhaps, be an individual characteristic unrelated to  his potential powers. However, it is not possible, from the evidence  presented so far, to conclude that wizarding is a heritable trait.

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你要是觉得讨论就在一团雾水中结束，那你就错了，来自牛津大学的学者2007在British Medical Journal（很牛的医学类杂志，2008年影响因子13.66）上提出了Magical enhancer element（魔法增强子原件）的概念
   
(Left) Magical enhancer element within a site of accessible chromatin in  human with ancestors all possessing magical abilities                                           (pureblood), which interacts  with transcriptional apparatus to drive gene expression. (Right)  Chromatin in non-magical human                                           (muggle) remains in an  inactive closed conformation
    魔法增强子在纯正的巫师染色体中可以帮助基因的转录，而在麻瓜中不起作用，对了，这个就是"表观遗传学"epigenetics, 大亮了
      BMJ  2007;  335                                                  :  1299   doi: 10.1136/bmj.39414.582639.BE  (Published                                                                                    20 December 2007)  

• Altered states

Origins of magic: review of genetic and epigenetic effects

•          Sreeram V Ramagopalan, DPhil candidate12,
•          Marian Knight, senior clinical research fellow3,
•          George C Ebers, professor of clinical neurology12,
•          Julian C Knight, senior research fellow1

    + Author Affiliations

•          1Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN
•          2Department of Clinical Neurology, University of Oxford
•          3National Perinatal Epidemiology Unit, University of Oxford

• Correspondence to: J C Knight http://www.renren.com/

•          Accepted 16 November 2007

Abstract
    Objective To assess the evidence for a genetic basis to magic.
    Design Literature review.
    Setting Harry Potter novels of J K Rowling.
    Participants Muggles, witches, wizards, and squibs.
    Interventions Limited.
    Main outcome measures Family and twin studies, magical ability, and specific magical skills.
    Results Magic  shows strong evidence of heritability, with familial aggregation and  concordance in twins. Evidence suggests magical                                  ability to be a quantitative trait.  Specific magical skills, notably being able to speak to snakes, predict  the future, and                                  change hair colour, all seem heritable.
    Conclusions A  multilocus model with a dominant gene for magic might exist, controlled  epistatically by one or more loci, possibly recessive                                  in nature. Magical enhancers regulating  gene expressionmay be involved, combined with mutations at specific  genes implicated                                  in speech and hair colour such as FOXP2  and MCR1.
IntroductionGenetic factors that underlie traits such as height1 and weight2 are currently under scrutiny using genome wide association methods, yet  the detection of genes predisposing to magic has                                  been given relatively short shrift.  Using the books by J K Rowling about Harry Potter, a schoolboy wizard,  to gain an insight                                  into humans with magical abilities, one  study suggested that magic is the result of a single gene.3 This assertion has been contentious, however, with another study questioning whether magic is heritable.4 We assessed the heritability of magic now that the Harry Potter series is complete with the publication of the seventh and                                  final book.5
    在参考文献中，不仅有上面两篇文献，还有全套的哈利波特，哈哈哈哈哈哈哈
References

•          Weedon MN, Lettre G, Freathy RM, Lindgren CM, Voight BF, Perry JR, et al. A common variant of HMGA2 is associated with adult                                              and childhood height in the general population. Nat Genet2007;39:1245-50.                    [CrossRef][Medline][Web of Science]        
•          Frayling TM, Timpson NJ, Weedon MN, Zeggini E, Freathy RM, Lindgren CM, et al. A common variant in the FTO gene is associated                                              with body mass index and predisposes to childhood and adult obesity. Science2007;316:889-94.                    [Abstract/FREE Full text]        
•          Craig JM, Dow R, Aitken M. Harry Potter and the recessive allele. Nature2005;436:776.                    [Medline]        
•          Dodd A, Hotta C, Gardner M. Harry Potter and the prisoner of presumption. Nature2005;437:318.                    [Medline]        
•          Rowling JK. Harry Potter and the deathly hallows. London: Bloomsbury, 2007.
•          Rowling JK. Harry Potter and the philosopher’s stone. London: Bloomsbury, 1997.
•          Rowling JK. Harry Potter and the chamber of secrets. London: Bloomsbury, 1998.
•          Rowling JK. Harry Potter and the prisoner of Azkaban. London: Bloomsbury, 1999.
•          Rowling JK. Harry Potter and the goblet of fire. London: Bloomsbury, 2000.
•          Rowling JK. Harry Potter and the order of the phoenix. London: Bloomsbury, 2003.
•          Rowling JK. Harry Potter and the half-blood prince. London: Bloomsbury, 2005