DNA 离开染色体会怎么样？ 几乎细胞内的所有类型的分子都具有信号调节作用。蛋白就不用多说了，胰岛素是激素的典型代表，细胞内的各类蛋白激酶是信号传导最重要的成员，属于蛋白质。各种细胞因子和转录因子是蛋白质和肽，更不要说众多神经肽。脂质的信号也许多，这方面是前列腺素为典型代表的炎症介质。小分子以几种气体为典型，一氧化碳、一氧化氮和硫化氢为代表。各类离子、各类自由基或活性氧。最近发现小 RNA 在细胞内强大的信号作用。物理化学信号，光线、声音、空间位置和震动、摩擦、温度、压迫等等，信号的类型太多了，甚至可以说，存在于细胞内外环境的所有信息都有可能参与细胞功能的调节，都可能属于信号。 染色体中的 DNA 是负责基因信息储存的，是一种具有高度特定职能的信息分子。沃森克里克因为提出 DNA 是遗传物质和双螺旋结构而获得诺贝尔医学生理学奖。 DNA 可以说是家喻户晓的明星分子了。 上述背景下，我思考的问题是，既然细胞内所有的分子都可以是信号分子，小 RNA 是重要的信号分子，那么小 DNA 是否也是一种信号分子。什么时候有小 DNA ？我不清楚正常细胞内会不会出现小 DNA 。但在被病毒感染的细胞内肯定可以出现 DNA 。这种 DNA 是否具有信号作用，肯定可以有。有一些人，例如一些自身免疫性疾病患者身体内， DNA 是可以作为一种抗原被免疫细胞识别，这显然就是一种信号现象，被免疫细胞识别意味着可以被其他细胞识别，被识别就是被信号。在组织细胞受到伤害的时候，细胞核内释放出自身的 DNA 片断，这些小片断会不会对自身或其他细胞产生信号影响，会不会成为身体的致病因子。组蛋白可以作为一种促进炎症发生的因素，那么 DNA 片断也有可能具备类似的性质。我认为这种可能是非常大的，甚至也许是非常重要的。 如果能证明这个现象，应该可以发表在 CNS 上没有问题。简单的方法是将一些细胞的 DNA 进行纯化和切割，然后注射到动物身体内，看是否能产生一些影响。如果有，那么就可以确定这种影响的细节，也就可以确定这种现象。
人的生长发育甚至很多疾病和行为是由遗传物质决定的。有关科学家曾经想，把人类基因组中的序列全部测一遍，就可以知道基因组中有什么，就可以揭示人类生长发育、疾病、行为等多方面的分子机理。很多科学家付出了多年的努力，人类基因组测完了，哪一条染色体上什么位置是什么碱基知道了。 但我们仍然不知道大多数碱基序列是干什么的，有什么用。于是，又一个大型项目产生了，the Encyclopedia of DNA Elements（ENCODE）。这个项目的目标是为人类基因组建立一个百科全书，你想知道哪一段有什么用，直接查询就行了。最近ENCODE在PLoS Biology上发表了这本百科全书的使用说明，" A User's Guide to the Encyclopedia of DNA Elements (ENCODE) "。很惭愧，作为相关研究的教师，我竟然没注意到这篇论文。今天 的Nature为该文做了一个广告，HIGHLIGHTS了一下， Genomics: A guided tour of the genome 。其中举了一例“ENCODE data helped to clarify how a DNA region upstream of a cancer-promoting gene called c- Myc regulates the gene: by attracting and binding proteins that enhance its expression.” 这篇文章值得一读。对相关研究的科研人员和研究生，应该属于必读材料。 人类基因组测序的总结论文见“ 人类基因组测序的意义--重要文献推荐 ”。
2001年2月12日，由6国的科学家共同参与的国际人类基因组公布了人类基因组图谱及初步分析结果。这个被誉为生命科学“登月计划”的研究项目取得重大进展，为人类揭开自身奥秘奠定了坚实的基础。美、英、法、德、日和中国6国先后参加人类基因组对23对染色体DNA大规模测序的国际合作，最终绘制了一张类似化学元素周期表的人类基因组精确图谱。 【科学时报】2010：基因组学推动生命科学大步向前 http://news.sciencenet.cn/htmlnews/2011/2/243802.shtm 《自然》社论关注人类基因组测序 http://news.sciencenet.cn/htmlnews/2011/2/243743.shtm 十年前，有人认为人类基因组工程是人类历史的伟大成就，就如登陆月球和发明车轮一般。不过现在就将基因组测序载入史册还为时过早，我们必须在此基础上取得更大的成绩才能实现基因组测序的真正成功。 人类基因组研究主管《Nature》点评测序发展 http://www.ebiotrade.com/newsf/2011-2/2011211172539857.htm 本周出版的《Nature》杂志封面是一只点亮的灯，而这盏灯发出光芒的灯丝则是人类基因组的DNA双螺旋结构……，今年是人类基因组草图公布后的第十个年头，来自美国国立卫生研究院人类基因组研究所NHGRI的主管：Eric D. Green等人著文“Charting a course for genomic medicine from base pairs to bedside”，描绘了基因组测序的未来蓝图，也提醒基因组测序还需要更多的成绩才能实现真正的成功。 Best is yet to come Ten years after the human genome was sequenced, its promise is still to be fulfilled. http://www.nature.com/nature/journal/v470/n7333/full/470140a.html 全球专家拟绘癌症基因图谱 http://news.163.com/08/0501/07/4AREF8ES000120GU.html
科学家揭秘急性癌症成因：染色体爆炸破坏DNA http://news.sciencenet.cn/htmlnews/2011/1/242576.shtm 英国科学家找到了急性癌症的形成原因：细胞内的染色体发生爆炸破坏了DNA，从而让人有可能在短时间内患上癌症。 Why some cancers seems to develop in an instant - cells can explode wreaking havoc in DNA http://www.dailymail.co.uk/health/article-1344740/Why-cancers-develop-instant--cells-explode-wreaking-havoc-DNA.html The mystery of 'instant cancers' - tumours that seem to appear out of nowhere - has been solved by British scientists. In some cases, a single apocalyptic explosion in a cell can cause as much damage to the DNA as decades of hard living. http://arrowsmith.psych.uic.edu/cgi-bin/arrowsmith_uic/edit_b.cgi Start A-Literature C-Literature B-list Filter Literature A-query: instant cancers C-query: DNA damage The B-list contains title words and phrases (terms) that appeared in both the A and the C literature. 6 articles appeared in both literatures and were not included in the process of computing the B-list but can be viewed here . The results of this search are saved under id # 13989 and can be accessed from the start page after you leave this session. There are 426 terms on the current B-list ( 89 are predicted to be relevant), which is shown ranked according to predicted relevance. The list can be further trimmed down using the filters listed in the left margin. To assess whether there appears to be a biologically significant relationship between the AB and BC literatures for specific B-terms, please select one or more B-terms and then click the button to view the corresponding AB and BC literatures. Use Ctrl to select multiple B-terms. job id # 13989 started Sun Jan 9 22:35:53 2011 Max_citations: 50000 Stoplist: /var/www/html/arrowsmith_uic/data/stopwords_pubmed Ngram_max: 3 13989 Search ARROWSMITH A A_query_raw: instant cancersSun Jan 9 22:36:11 2011 A query = instant cancers started Sun Jan 9 22:36:11 2011 A query resulted in 212 titles 13989 Search ARROWSMITH C C_query_raw: DNA damage Sun Jan 9 22:36:41 2011 C: DNA damage 85835 A: pubmed_query_A 212 AC: ( instant cancers ) AND ( DNA damage ) 6 C query = DNA damage started Sun Jan 9 22:36:42 2011 C query resulted in 50000 titles A AND C query resulted in 6 titles 1344 B-terms ready on Sun Jan 9 22:40:06 2011 Sem_filter: Concepts Ideas 426 B-terms left after filter executed Sun Jan 9 22:45:48 2011 B-list on Sun Jan 9 22:46:25 2011 1 non small cell 2 small cell lung 3 cancer xenograft 4 time rt pcr 5 linear quadratic 6 real time rt 7 small cell 8 melanoma progression 9 acute myeloid 10 superficial bladder 11 xenograft 12 chronic lymphocytic 13 treatment arsenic trioxide 14 b cell chronic 15 quantitative real time 16 nci 17 superficial bladder cancer 18 patient colorectal 19 formation lung 20 overexpression 21 intravesical 22 solitary fibrous tumor 23 cell chronic lymphocytic 24 colorectal 25 radiotherapy 26 chemotherapy 27 alteration apoptosis 28 specific cytotoxic t 29 orthotopic model 30 real time 31 surface plasmon 32 cancer therapy 33 estrogen receptor er 34 enhanced ultrasound induced 35 advanced breast cancer 36 myeloid 37 red fluorescent 38 status breast cancer 39 study oxidative 40 diagnosis breast cancer 41 focused ultrasound 42 duplication 43 fractionated radiotherapy 44 rt 45 bone health 46 antitumor action 47 primary breast 48 testicular 49 nasopharyngeal 50 cell specific 51 protein overexpression 52 oxidative 53 cell chronic 54 acute lymphoblastic 55 term exposure 56 multiple melanoma 57 radical 58 complex a 59 mechanistic 60 beam 61 specific cytotoxic 62 strategy induce tumor 63 ovarian 64 dosimetry 65 intraepithelial 66 lymphocytic 67 arrest 68 effect coffee 69 prostatic 70 online 71 fusion 72 mechanism antitumor 73 population based 74 neutron 75 axillary 76 medium term 77 proliferation 78 interleukin-6 level 79 primary liver 80 allogeneic stem cell 81 activator 82 scattering 83 allogeneic 84 heavy 85 endocrine treatment 86 rectal 87 worker 88 nuclear 89 orthotopic http://arrowsmith.psych.uic.edu/cgi-bin/arrowsmith_uic/show_sentences.cgi Start A-Literature C-Literature B-list Filter Literature AB literature B-term BC literature instant cancers small cell lung DNA damage 1: Involvement of calcium in the differential induction of heat shock protein 70 by heat shock protein 90 inhibitors, geldanamycin and radicicol, in human non -small cell lung cancer H460 cells.2006 Add to clipboard 1: Identification of microRNA profiles in docetaxel-resistant human non -small cell lung carcinoma cells (SPC-A1).2010 Add to clipboard 2: The close correlation between 8-hydroxy-2'-deoxyguanosine and epidermal growth factor receptor activating mutation in non -small cell lung cancer.2010 Add to clipboard 3: Genetic variation in glutathione metabolism and DNA repair genes predicts survival of small-cell lung cancer patients.2010 Add to clipboard 4: Targeting Epidermal Growth Factor Receptor-Associated Signaling Pathways in Non -Small Cell Lung Cancer Cells: Implication in Radiation Response.2010 Add to clipboard 5: Curcumin Induces Apoptosis in Human Non -small Cell Lung Cancer NCI-H460 Cells through ER Stress and Caspase Cascade- and Mitochondria-dependent Pathways.2010 Add to clipboard 6: Hypermethylation of growth Arrest DNA-damage-inducible gene 45 in non -small cell lung cancer and its relationship with clinicopathologic features.2010 Add to clipboard 7: 2010 Add to clipboard 8: Combinations of DNA Methyltransferase and Histone Deacetylase Inhibitors Induce DNA Damage in Small Cell Lung Cancer Cells: Correlation of Resistance with IFN-Stimulated Gene Expression.2010 Add to clipboard 9: NPRL2 Sensitizes Human Non -Small Cell Lung Cancer (NSCLC) Cells to Cisplatin Treatment by Regulating Key Components in the DNA Repair Pathway.2010 Add to clipboard 10: A Phase I Study of Concurrent Chemotherapy (Paclitaxel and Carboplatin) and Thoracic Radiotherapy with Swallowed Manganese Superoxide Dismutase (MnSOD) Plasmid Liposome (PL) Protection in Patients with Locally Advanced Stage III Non -Small Cell Lung Cancer.2010 Add to clipboard 11: The Nitric Oxide Prodrug JS-K is Effective Against Non -small Cell Lung Cancer Cells in vitro and in vivo : Involvement of Reactive Oxygen Species.2010 Add to clipboard 12: No evidence of an association of ERCC1 and ERCC2 polymorphisms with clinical outcomes of platinum-based chemotherapies in non -small cell lung cancer: A meta-analysis.2010 Add to clipboard 13: Effect of Ganoderma on drug-sensitive and multidrug-resistant small-cell lung carcinoma cells.2009 Add to clipboard 14: Sensitization to gamma-irradiation-induced cell cycle arrest and apoptosis by the histone deacetylase inhibitor trichostatin A in non -small cell lung cancer (NSCLC) cells.2009 Add to clipboard 15: XPG mRNA expression levels modulate prognosis in resected non -small-cell lung cancer in conjunction with BRCA1 and ERCC1 expression.2009 Add to clipboard 16: Epigenetic inactivation of checkpoint kinase 2 gene in non -small cell lung cancer and its relationship with clinicopathological features.2009 Add to clipboard 17: Single nucleotide polymorphism at rs1982073:T869C of the TGFbeta 1 gene is associated with the risk of radiation pneumonitis in patients with non -small-cell lung cancer treated with definitive radiotherapy.2009 Add to clipboard 18: Expression of an X-family DNA polymerase, pol lambda, in the respiratory epithelium of non -small cell lung cancer patients with habitual smoking.2009 Add to clipboard
自交植物中的LD覆盖范围都比较大,但LD在不同的群体,不同的染色体区域都不一样.下面这篇文章比较特别,自交植物LD 2kb Sela, H., Loutre, C., Keller, B., Schulman, A., Nevo, E., Korol, A., and Fahima, T. Rapid linkage disequilibrium decay in the Lr10 gene in wild emmer wheat (Triticum dicoccoides) populations. TAG Theoretical and Applied Genetics 122, 175-187. Lr10 该研究用的群体较小 58 accessions,标记密度高Lr10 was sequenced 拟南芥LD 10kb Recombination and linkage disequilibrium in Arabidopsis thaliana Recombination and linkage disequilibrium in Arabidopsis thaliana.pdf 水稻LD 1 temperate japonica500kb,tropical japonica 150kb indica 75kb(The Extent of Linkage Disequilibrium in Rice (Oryza sativa L.)) Recombination and linkage disequilibrium in Arabidopsis thaliana.pdf 2 indica 123kb,japonica 167kb(Genome-wide association studies of 14 agronomic traits in rice landraces) Genome-wide+association+studies+of+14+ag....pdf 3 20-30cM,Association mapping of yield and its components in rice cultivars Association mapping of yield and its components in rice cultivars.pdf 这个嘛,由于用的比较少,就太粗糙了 为什么要关注这个东西呢?它决定了作图的精度
根据国外报道，男孩的智商主要由母亲决定，女孩的智商由父母双方决定。父亲主要决定子女的性格。详情请看下面的报道： Thank Dad for Drive - but Thank Mom for Brains... Success in almost any field depends more on energy and drive than it does on intelligence. This explains why we have so many stupid leaders. - Sloan Wilson New York - Another blow to male self-esteem. Researchers say mothers alone may pass on the genes which determine a child's intellectual power, while fathers impart those genes controlling more instinctual, primitive mental functions. An article in this week's New Scientist magazine says studies in mice are revealing that the mother's genes contribute more to the development of the 'thinking' or 'executive' centres of the brain, while paternal genes have a greater impact on the development of the 'emotional' limbic brain. Ongoing research at England's Cambridge University is exploring what scientists call imprinted genes, and their role in reproduction and evolution. Imprinted genes differ from other genes in that their activation within the developing child depends upon the sex of the parent from which the gene came. Some imprinted genes work only if they come from the mother, the New Scientist article explains. The same gene is silenced if it is inherited via the sperm rather than the egg. Cambridge scientists stumbled upon this fact in 1984, during research that sought to discover if mammals could grow into maturity when supplied with the genes of just one parent. But they found such androgenetic (mouse) embryos died, because certain vital genes had been switched off by the (donor) father. Delving deeper into this phenomenon, researchers realised that certain genes controlling the development of the conscious, higher level of brain function - intelligence - are silenced in the paternal version, but operative in the maternal one. Conversely, genes controlling more primitive limbic function - emotions, and the drives to eat, copulate, and compete - are silenced in the mother's genes, but activated in the father's. In another study, Cambridge researchers examined the brain development of mouse embryos, abnormally weighted with extra amounts of the genes of either one parent or the other. As the embryos matured cells that carried only paternal genes accumulated in clusters scattered throughout the 'emotional' brain - the hypothalamus, the amygdala, New Scientist reports. In embryos with maternally supplied genetic material, cells containing only maternal genes were absent from the emotional brain. Instead, they selectively accumulated in the brain's executive region (the seat of higher, cognitive intelligence). Of course mice and men do differ. It is very important work, and very, very promising, says Wolf Reik, who is studying the imprinting phenomenon at the Babraham Institute, near Cambridge. However, he admits that, at this stage everyone is a little bit lost as to what it really means. But some psychologists are already trumpeting the discoveries as vindication of Freudian theory. Christopher Badcock, author of PsychoDarwinism , believes paternal genes help build Freud's famous id - the instinctual, emotional, unconscious self-while the mother's genes are behind the more rational, conscious ego. During development, maternal and paternal genes compete for control of behaviour, Badcock writes, culminating in a mind divided into two conflicting parts strikingly similar to Freud's ego and id. Whatever the psychological implications, experts believe imprint genes (of which only three or four have been identified so far) may number in the hundreds or thousands. Improperly switched on or off, they could also be the cause of numerous genetically inherited diseases. Researchers say more research may lead to ways of controlling the expression of such genes - and reversing the progress of these conditions. Source: Reuters Friday 26 May 1998 from New Scientist 3 May 1997 pages 34 - 39 If you came directly to this page, you may wish to press the Back button below to read the Nature article Mother and Father in Surprising Genetic Agreement on the previous page as its topic is very similar. For Motherly X Chromosome, Gender Is Only the Beginning by Natalie Angier As May dawns and the mothers among us excitedly anticipate the clever e-cards that we soon will be linking to and the overpriced brunches that we will somehow end up paying for, the following job description may ring a familiar note: Must be exceptionally stable yet ridiculously responsive to the needs of those around you; must be willing to trail after your loved ones, cleaning up their messes and compensating for their deficiencies and selfishness; must work twice as hard as everybody else; must accept blame for a long list of the worlds illnesses; must have a knack for shaping young minds while in no way neglecting the less glamorous tissues below; must have a high tolerance for babble and repetition; and must agree, when asked, to shut up, fade into the background and pretend you dont exist. As it happens, the above precis refers not only to the noble profession of motherhood to which we all owe our lives and guilt complexes. It is also a decent character sketch of the chromosome that allows a human or any other mammal to become a mother in the first place: the X chromosome. The X chromosome, like its shorter, stubbier but no less conspicuous counterpart, the Y chromosome, is a so-called sex chromosome, a segment of DNA entrusted with the pivotal task of sex determination. A mammalian embryo outfitted with an X and Y chromosomal set buds into a male, while a mammal bearing a pair of X chromosomes emerges from the maternal berth with birthing options of her own. Yet the X chromosome does much more than help specify an animals reproductive plumbing. As scientists who study the chromosome lately have learned, the X is a rich repository of genes vital to brain development and could hold the key to the evolution of our particularly corrugated cortex. Moreover, the X chromosome behaves unlike any of the other chromosomes of the body - unlike little big-man Y, certainly, but also unlike our 22 other pairs of chromosomes, the self-satisfied autosomes that constitute the rest of our genome, of the complete DNA kit packed into every cell that we carry. It is a supple, switchbacking, multitasking gumby doll patch of the genome; and the closer you look, the more Cirque du Soleil it appears. Although the precise details of its chemical structure and performance are only just emerging, the X chromosome has long been renowned among geneticists, who named it X not because of its shape, as is commonly presumed - the non-sex chromosomes also vaguely resemble an X at times during cell division - but because they were baffled by the way it held itself apart from the other chromosomal pairs. They called it X for unknown, said Mark T Ross of the X Chromosome Group at the Wellcome Trust Sanger Institute in Cambridge. (When its much tinier male counterpart was finally detected, researchers simply continued down the alphabet for a name.) Many of the diseases first understood to be hereditary were linked to Xs span, for the paradoxical reason that such conditions showed their face most often in those with just a single X to claim: men. Scientists eventually determined that we inherit two copies of our 23,000 or so genes, one from each parent; and that these genes, these chemical guidelines for how to build and maintain a human, are scattered among the 23 pairs of chromosomes, along with unseemly amounts of apparent chemical babble. Having two copies of every gene proves especially handy when one of those paired genes is defective, at which point the working version of the gene can step in and specify enough of the essential bodybuilding protein that the baby blooms just fine and may never know its DNA is hemi-flawed. And here is where the Ys petite stature looms large. Because it holds a mere 50ish different genes against its counterparts 1,100, the vast majority of X-based genes have no potential pinch-hitter on the Y. A boy who inherits from his mother an X chromosome that enfolds a faulty gene for a bloodclotting factor, say, or for a muscle protein or for a color receptor wont find succor in the chromosomal analogue bestowed by Dad. He will be born with hemophilia, or muscular dystrophy, or color-blindness. But, hey, he will be a boy, for male-making is the task to which the Y chromosome is almost exclusively devoted. In fact, it is to compensate for the monomania of the Y that the X chromosome has become such a mother of a multitasker. Over the 300 million years of evolution, as the Y chromosome has shrugged off more of its generic genetic responsibilities in pursuit of sexual specialization, the X has had to pick up the slack. It, too, has pawned off genes to other chromosomes. But for those genes still in its charge, the X must double their output, to prod each gene to spool out twice the protein of an ordinary gene and thus be the solo equivalent of any twinned genes located on other, nonsexy chromosomes. Ah, but women, who have two X chromosomes, two copies of those 1,100 genes: What of them? With its usual Seussian sense of playfulness, evolution has opted to zeedo the hoofenanny. In a girls cells, you dont see two pleasantly active X chromosomes behaving like two ordinary nonsex chromosomes. You see one hyperactive X chromosome, its genes busily pumping out twice the standard issue of protein, just as in a boys cells; and you see one X chromosome that has been largely though not wholly shut down, said Laura Carrel, a geneticist at Penn State College of Medicine. Through an elaborate process called X inactivation, the chromosome is blanketed with a duct tape of nucleic acid. In some cells of a womans body it may be the chromosome from Dad thats muffled, while in other cells the maternal one stays mum. Every daughter, then, is a walking mosaic of clamorous and quiet chromosomes, of fatherly sermons and maternal advice, while every son has but his mothers voice to guide him. Remember this, fellows: you are all mamas boys. Source: nytimes.com 1 May 2007 IQ Is Inherited, Suggests Twin Study by Alison Motluk Genes have a very strong influence over how certain parts of our brains develop, scientists in the US and Finland have found. And the parts most influenced are those that govern our cognitive ability. In short, you inherit your IQ. Paul Thompson at the University of California at Los Angeles and his colleagues used MRI to scan the brains of 10 pairs of identical and 10 pairs of fraternal twins. Identical twins have identical genes, whereas fraternal twins sharing on average half their genes. The twins shared environments, means researchers can separate genetic and environmental factors. The researchers found that certain regions of the brain were highly heritable. These included language areas, known as Broca's and Wernicke's areas, and the frontal region, which, among other things, plays a huge role in cognition. In identical twins, these areas showed a 95 to 100% correlation between one twin and the other - they were essentially the same. The frontal structure, says Thompson, appears to be as highly influenced by genes as the most highly influenced trait we know of - fingerprints. It's extraordinary how similar they are, he says. The finding suggests that environment - their experiences, what they learned in life, who they knew - played a negligible role in shaping it. Fraternal twins were near-identical in Wernicke's area, but less similar in other areas, with about 60 to 70% correlation. Random pairs of people would be expected to have no correlation. Intellectual function The study was all the more interesting in that it found that not only was this gray matter highly heritable, but it affected overall intelligence as well. We found that differences in frontal gray matter were significantly linked with differences in intellectual function, the authors write. The volunteers each took a battery of tests that examined 17 separate abilities, including verbal and spatial working memory, attention tasks, verbal knowledge, motor speed and visuospatial ability. These tests hone in on what's known as g, the common element measured by IQ tests. People who do well on one of these tests tend to do well on them all, says Thompson. It is not known what exactly g is. But these new findings suggest that g is not just a statistical abstraction, but rather, that it has a biological substrate in the brain, says Robert Plomin, of the Institute of Psychiatry in London. Plomin has spent eight years looking for genes behind g. I'm convinced that there are genes, he says, a lot of them, each with a small effect. Stephen Kosslyn of Harvard University in Boston questions whether g should really be called intelligence. G picks up on abilities such as being able to abstract rules or figure out how to order things according to rules. It's the kind of intelligence you need to do well in school, he says. Not what you need to do well in life. Journal reference: Nature Neuroscience (DOI: 10.1038/nn758) Source: newscientist.com 5 November 2001 Stephen Kosslyn appears to be good at abstracting rules and at figuring out how to order things according to rules. Do you suppose that means he hasn't done well in life? Or is that a faulty syllogism? Can you have a high IQ and also have those characteristics you need to do well in life? This article doesn't address that issue. If you can't have both, then can we safely assume that all wealthy people are stupid? See also: Clones of Nature (in the Science section) - for some interesting facts about (mostly identical) twins... Reunions Set off Sex Urges (in the section on Relationships) - When meeting their lost relative for the first time the respondents all experienced an overwhelming and complicated rush of emotions and an almost irresistible sense of falling in love. They all said they had a need to discover an unusual form of closeness and intimacy with their relative, who had felt the same way. Twins in Black and White (in the section on Oddities) - for information on some unusual pairs of twins... To embark on a series of IQ-type tests, including an eighth-grade exam from Kansas in 1895, history and world affairs questions drawn from The Economist , an IQ test from 1970s England, a 4-question Mensa test from today, a visual test of an area problem, and a brief tongue-in-cheek test of creative thinking, see the Intellectual and Entertaining section. Or have your girlfriend do it. Brain Games (in the animation section) - requires a fast connection and Flash. 100 Facts (in the odds and oddities section) - I'll bet you don't know most of them... Realise that your wife/girlfriend/mistress can be lovely and her brains don't matter (and may even get in the way). But the mother of your children (if you want them to grow up not being a burden on you) should at least know how to spell... Moms' Poor Vocabulary Hurts Kids' Future by Karen S Peterson Mothers should teach letters to their babies, talk out loud to them and read books to them regularly and consistently. This is much less likely to happen when the mother is trapped on the bottom rungs of the socioeconomic ladder. - Study co-author George Farkas If a child comes from an economically deprived home with a mom who has a poor vocabulary, by the age of 3 his fate just may be sealed: he will possibly never catch up in school and have lifelong struggles with learning, a new study shows. Those children in our society who grow up in poverty or near poverty are adversely affected by their mother's own vocabulary deficit during their earliest years, when they are learning to speak at home, says George Farkas, a Penn State sociologist and co-author of the study. The vocabulary gap suffered by children emerges at the earliest ages in both disadvantaged black and white homes, he says, and becomes dramatic by 36 months, Farkas says. The problem lessens once a child is in school and comes in contact with verbal teachers and others. By the time the child is 6 and enters first grade, the vocabulary gap doesn't widen any further, Farkas says. After starting school, there is an upward-looking growth curve for the disadvantaged kids that remains parallel with those from more middle-class homes. But his research shows the economically deprived children never truly recover from the damage done in the early, preschool years. Typically, such youngsters don't read as quickly or as well. The first-grade teacher usually is told to get students reading by Christmas, Farkas says. If students come from low-income backgrounds, with a limited vocabulary and often non-standard English grammar and pronunciation, they are in a big predicament. Not only must Mom be reasonably verbal, Farkas finds, but she must instruct in a sufficiently warm and attractive manner so that the lesson takes. It is, he says, necessary for mothers to teach letters to their babies, talk out loud to them and read books to them regularly and consistently. This is much less likely to happen when the mother is trapped on the bottom rungs of the socioeconomic ladder and is consumed by financial and emotional pressures or stresses. Farkas analysed a variety of findings from the National Longitudinal Survey of Youth Data, which is funded in part by the federal government. He analysed separately 3,500 white and 3,300 black children tracked periodically between ages 3 and 12, concentrating on socio-economic classes in each racial group. His findings, he says, show the need for government policies that will reach out to the youngest children in order to create school-readiness skills. Educators and child development specialists have long known about the significance of early vocabulary skills, says Ted Feinberg of the National Association of School Psychologists. We know how critically important vocabulary is to all of the additional learning skills that are required of schoolchildren throughout their school careers, he says. If they do not have a solid foundation in vocabulary, it does not surprise me that they continue to lag behind. Source: USA Today 12 April 2001 I'm not sure Farkas' study clearly separates cause and effect. If the mothers had a great vocabulary and lots of unstressed time to talk to and play with their kids, they probably wouldn't be at the bottom of the socioeconomic ladder in the first place. A good vocabulary is a problematical term anyway - a child growing up in a black ghetto may in fact have a wide vocabulary, able to employ lots of words YOU may never have heard of. Besides, if IQ is inherited from the mother, if she is below average in her skills, is it that surprising her children might be as well? See also: The Vocabulary Deficit (in the education section) - The shortfall in vocabulary is easy enough to explain. A study by well-regarded researchers concludes that the number of words children hear addressed to them increases dramatically with family income. A child of professionals is likely to hear as many as 50 million words by age 4. The child of a welfare parent may be exposed to just a quarter of that number... The Social Market (in the society section) - suppose a deprived single mother, instead of relying on the State or child support, has to fund her offspring by issuing share capital in it. To attract investors (including the father), she will have to bring it up as best she can, keep it out of crime and not burden her portfolio with further potential loss-makers. lf she fails, the child's share price will decline, and it may be taken over by another mother or a specialised institution which can manage it better... For more articles related to Men including sperm donations on the net, the effects of testosterone, condom sizes, buddies, smells, nagging, gyncologists, mid-life crises, fathers and more click the Up button below to take you to the Table of Contents page for this section. 来源： http://www.flatrock.org.nz/topics/men/thank_mom_for_brains.htm
The organization and function of chromosomes Baird DM, Farr CJ. The organization and function of chromosomes. EMBO Rep. 2006 Apr; 7 (4): 372-6. Epub 2006 Mar 17 The organization and function of chromosomes Genomes, genes and junk, the large scale organization of chromosomes Schmidt T, Heslop-Harrison JS. Genomes, genes and junk, the large scale organization of chromosomes. Trends Plant Sci. 1998 May; 3 (5): 195-9 Genomes, genes and junk, the large scale organization of chromosomes Heterochromatin revisited Grewal SI, Jia S. Heterochromatin revisited. Nat Rev Genet. 2007 Jan; 8 (1): 35-46 The formation of heterochromatin, which requires methylation of histone H3 at lysine 9 and the subsequent recruitment of chromodomain proteins such as heterochromatin protein HP1, serves as a model for the role of histone modifications and chromatin assembly in epigenetic control of the genome. Recent studies in Schizosaccharomyces pombe indicate that heterochromatin serves as a dynamic platform to recruit and spread a myriad of regulatory proteins across extended domains to control various chromosomal processes, including transcription, chromosome segregation and long-range chromatin interactions. Heterochromatin revisited Plant chromosomes from end to end: telomeres, heterochromatin and centromeres Lamb JC , Yu W , Han F , Birchler JA . Plant chromosomes from end to end: telomeres, heterochromatin and centromeres. Curr Opin Plant Biol. 2007 Apr; 10 (2): 116-22. Epub 2007 Feb 8. Recent evidence indicates that heterochromatin in plants is composed of heterogeneous sequences, which are usually composed of transposable elements or tandem repeat arrays. These arrays are associated with chromatin modifications that produce a closed configuration that limits transcription. Centromere sequences in plants are usually composed of tandem repeat arrays that are homogenized across the genome. Analysis of such arrays in closely related taxa suggests a rapid turnover of the repeat unit that is typical of a particular species. In addition, two lines of evidence for an epigenetic component of centromere specification have been reported, namely an example of a neocentromere formed over sequences without the typical repeat array and examples of centromere inactivation. Although the telomere repeat unit is quite prevalent in the plant kingdom, unusual repeats have been found in some families. Recently, it was demonstrated that the introduction of telomere sequences into plants cells causes truncation of the chromosomes, and that this technique can be used to produce artificial chromosome platforms. Plant chromosomes from end to end Planning for remodeling: nuclear architecture, chromotin and chromosomes Heslop-Harrison JS. Planning for remodelling: nuclear architecture, chromatin and chromosomes. Trends Plant Sci. 2003 May; 8 (5): 195-7 DNA sequences occupy three-dimensional positions and their architecture is related to gene expression, gene-protein interactions and epigenetic processes. The recent analysis of chromosome 4 in Arabidopsis interphase nuclei reveals that gene-rich, undermethylated DNA is composed of active loops of 200 to 2000 kb associated with acetylated histones, providing a well-defined model system to study chromatin in its nuclear context. Planning for remodeling-nuclear architecture, chromotin and chromosomes Advances in plant chromosome identification and cytogenetic techniques Kato A, Vega JM, Han F, Lamb JC, Birchler JA. Advances in plant chromosome identification and cytogenetic techniques. Curr Opin Plant Biol. 2005 Apr; 8 (2):148-54. Recent developments that improve our ability to distinguish slightly diverged genomes from each other, as well as to distinguish each of the nonhomologous chromosomes within a genome, add a new dimension to the study of plant genomics. Differences in repetitive sequences among different species have been used to develop multicolor fluorescent in situ hybridization techniques that can define the components of allopolyploids in detail and reveal introgression between species. Bacterial artificial chromosome probes and repetitive sequence arrays have been used to distinguish each of the nonhomologous somatic chromosomes within a species. Such karyotype analysis opens new avenues for the study of chromosomal variation and behavior, as well as for the localization of individual genes and transgenes to genomic position. Advances in plant chromosome identification and cytogenetic techniques Reinterpreting pericentrimeric Heterochromatin Topp CN, Dawe RK. Reinterpreting pericentromeric heterochromatin. Curr Opin Plant Biol. 2006 Dec; 9 (6): 647-53. Epub 2006 Oct 2 In fission yeast, pericentromeric heterochromatin is directly responsible for the sister chromatid cohesion that assures accurate chromosome segregation. In plants, however, heterochromatin and chromosome segregation appear to be largely unrelated: chromosome transmission is impaired by mutations in cohesion but not by mutations that affect heterochromatin formation. We argue that the formation of pericentromeric heterochromatin is primarily a response to constraints on chromosome mechanics that disfavor the transmission of recombination events in pericentromeric regions. This effect allows pericentromeres to expand to enormous sizes by the accumulation of transposons and through large-scale insertions and inversions. Although sister chromatid cohesion is spatially limited to pericentromeric regions at mitosis and meiosis II, the cohesive domains appear to be defined independently of heterochromatin. The available data from plants suggest that sister chromatid cohesion is marked by histone phosphorylation and mediated by Aurora kinases. Reinterpreting pericentrimeric Heterochromatin
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