《Science》: Breakthrough of the Year

1.The Poincaré Conjecture--Proved
庞加莱猜想属于被称为拓扑的数学分支，通常被描述成“橡皮上的几何”，因为它涉及能够经历任意拉伸的表面。这个1904年由庞加莱提出的猜想描述一个空间是否与“超球面”(四维球体的三维表面)等价的检验。 基本上与外界隔绝地工作了7年的俄罗斯数学家Grigori Perelman 2002年在互联网上提交了三篇文章的第一篇，这些文章把庞加莱猜想作为一个更雄心勃勃的结果的一部分，给其证明提供了一个轮廓。但是在2003年访问美国之后，这位俄罗斯数学隐士回国后停止了与外界的电话和电子信往来。到了2006年，其他人终于赶了上来。三个独立的小组写出报告填补了佩雷尔曼的证明中缺失的关键细节，现在佩雷尔曼的同行几乎都没有疑问地认为他证明了这个著名的难题。
2.DIGGING OUT FOSSIL DNA.
从化石中取出DNA: 研究人员用一种解码和分析DNA的新技术，从尼安德特人和猛犸化石中捕获到遗传信息。
3.SHRINKING ICE.
冰架在缩小: 研究人员今年记录了这一令人不安的趋势。南极洲和格陵兰岛的冰架都在以更快的速度消失到海洋中。
4.NEITHER FISH NOR FOWL.
鱼迈出的第一步: 一个具有结实的连接着的鳍的鱼化石的发现曾是2006年的头版新闻。这种鱼是有肢脊椎动物已知的最近亲，它为生命如何离开海洋登上陆地提供了一个视窗。
5.THE ULTIMATE CAMOUFLAGE.
隐身术的科学: 虽然它看上去一点也不像哈里波特的魔术披风，科学家今年制造的隐身“斗篷”是第一个将物体在视觉上屏蔽起来的初步装置。这个装置引导入射的微波使其既不反射、也没有影子。
6.A RAY OF HOPE FOR MACULAR DEGENERATION PATIENTS.
黄斑病变患者的希望: 研究一种被称为老年黄斑病变失明的研究人员揭示，药物ranibimuzab能改善某些患者的视觉，他们还找到了几个影响人们该症易患性的基因。
7.DOWN THE BIODIVERSITY ROAD
生物多样性是如何发生的: 从沙滩小鼠、到果蝇、到蝴蝶，这些不同的动物帮助科学家发现导致新物种进化的遗传变化。
8.PEERING BEYOND THE LIGHT BARRIER.
显微学的新前沿: 今年，生物学家用新的显微技术来帮助他们观察小于200纳米的细节，为了解细胞和蛋白质的精细结构提供了更清晰的视野。
9.THE PERSISTENCE OF MEMORY.
制造记忆: 2006年的几个发现使神经科学家对了解大脑如何记录新记忆更接近了一步。增强神经元之间连接的被称为“长时程增强”的过程看来很可能是记忆的基础。
10.MINUTE MANIPULATIONS.---piRNA
新一类的小RNA: 科学家发现了一类关闭基因表达的新小RNA分子，把它们命名为 "Piwi-干扰 RNA"。
本年度的崩溃-科学骗局: 干细胞研究者黄禹锡以及其合作者曾在《科学》发表两篇重要论文，他们制造的骗局在2006年被彻底调查了，本年度也发生了几起其它的科学不端行为。
值得注意的领域: 《科学》预测来年的热门领域和主题包括整基因组相关性研究、光晶格、寻找宇宙的原始氢、以及比较灵长类的基因组。

Science 22 December 2006:Vol. 314. no. 5807, p. 1841DOI: 10.1126/science.1138510
Editorial
Breakthrough of the Year
Donald Kennedy
Last year, evolution was the breakthrough of the year; We found it full of new developments in understanding how new species originate. But we did get a complaint or two that perhaps we were just paying extra attention to the lively political/religious debate that was taking place over the issue, particularly in the United States.
Perish the thought! Our readers can relax this year: Religion and politics are off the table, and n-dimensional geometry is on instead. This year's Breakthrough salutes the work of a lone, publicity-shy Russian mathematician named Grigori Perelman, who was at the Steklov Institute of Mathematics of the Russian Academy of Sciences until 2005. The work is very technical but has received unusual public attention because Perelman appears to have proven the Poincaré Conjecture, a problem in topology whose solution will earn a $1 million prize from the Clay Mathematics Institute. That's only if Perelman survives what's left of a 2-year gauntlet of critical attack required by the Clay rules, but most mathematicians think he will.
The analysis supplied by Dana Mackenzie on p. 1848 struck me as a fascinating exploration, full of metaphors suggesting a multidisciplinary dimension in Perelman's analysis. He first got interested in Ricci flow, a process by which topological regions of high curvature flow into regions of lower curvature. He also identified a quantity, which he called "entropy," that increased during the flow, providing a gradient. Tight spots in spatial connections block the application of these rules to dimensions higher than two, so Perelman dealt with these through "surgical intervention." This story is rich with borrowings: from fluid mechanics, thermodynamics, and even surgery! It's hard to deal with a three-dimensional object in four-dimensional space. Perelman's solution is a stunning triumph of intellect. Alas, it has led to bitter controversy, involving others but not Perelman.
Of course, in any Breakthrough year we are obliged to have a Breakdown. This time around, we had to blow the whistle on ourselves. In recognizing this as a year in which scientific fraud took center stage, it was clear that we had to lead with the story involving the retraction of two of our own papers, an event that drew worldwide press attention and required us to ask for an outside evaluation of how we had handled the papers. That brought us some tough news about how competitive the scientific enterprise has become, and the consequential incentive to push (or shred) the ethical envelope.
On the positive side, it was a rich year for important experimental studies. My favorites include some new explanations for how species originate, one of the daunting post-Darwinian puzzles. Among other examples, there is a clear case for speciation through hybridization, an exception to the more general rule that hybrids either don't make it or are reproductively incompetent. Because I like coastlines, when I see new evidence about sea-level rise, I pay attention. This year we got new measures of rates of glacial melting at both ends of the globe: in Greenland, where rates are in hundreds of gigatons a year, and in Antarctica, where drainage by ice streams is accelerating. I also follow the Neanderthal story, because it's interesting to ponder how different human species--now thought from archaeological evidence to have overlapped for perhaps 10,000 years--might have interacted. New sequencing of the Neanderthal genome indicates that the point of divergence is nearly half a million years old and opens up a wealth of comparisons with the human genome sequence. The question everyone asks--"Did they have sex?"--is still open, though barely.
All in all, it's not been a bad year. The predictions we made in 2005 of "Areas to Watch" turned out pretty well. We said RNA interference would be an active sector--good call. Cosmic-ray capture didn't work out, but there was the predicted level of activity on the "small worlds" of microbial communities. We predicted lots of activity on high-temperature superconductivity, and there were more applications, although less new theory. The worst miss was the prediction that the ivory-billed woodpecker would be re-found. Come on, birders, give us some help out there; a good photo, please, not the skin.
10.1126/science.1138510

Donald Kennedy is the Editor-in-Chief of Science.
The editors suggest the following Related Resources on Science sites:
In Science Magazine
NEWS BREAKTHROUGH OF THE YEAR: The Poincaré Conjecture--Proved
Dana Mackenzie (22 December 2006)Science 314 (5807), 1848. [DOI: 10.1126/science.314.5807.1848] Summary » Full Text » PDF »
NEWS BREAKTHROUGH OF THE YEAR: The Runners-Up
(22 December 2006)Science 314 (5807), 1850a. [DOI: 10.1126/science.314.5807.1850a] Summary » Full Text » PDF »
NEWS BREAKTHROUGH OF THE YEAR: Scorecard 2006
(22 December 2006)Science 314 (5807), 1850b. [DOI: 10.1126/science.314.5807.1850b] Summary » Full Text » PDF »
NEWS BREAKTHROUGH OF THE YEAR: BREAKDOWN OF THE YEAR: Scientific Fraud
Jennifer Couzin (22 December 2006)Science 314 (5807), 1853. [DOI:10.1126/science.314.5807.1853] Summary » Full Text » PDF »
NEWSBREAKTHROUGH OF THE YEAR: Areas to Watch in 2007
(22 December 2006)Science 314 (5807), 1854. [DOI: 10.1126/science.314.5807.1854] Summary » Full Text » PDF »


Papers and Articles on piRNA
A. Girard et al., "A Germline-Specific Class of Small RNAs Binds Mammalian Piwi Proteins," Nature 442, 199 (2006)
A. Aravin et al., "A Novel Class of Small RNAs Bind to MILI Protein in Mouse Testes," Nature 442, 203 (2006)
S.T. Grivna et al., "A Novel Class of Small RNAs in Mouse Spermatogenic Cells," Genes Dev. 20, 1709 (2006)
N.C. Lau et al., "Characterization of the piRNA Complex from Rat Testes; Science 313, 363 (2006)
R.W. Carthew, "A New RNA Dimension to Genome Control," Science 313, 305 (2006)Perspective article highlighting the Lau et al. study.
V.N. Kim, "Small RNAs Just Got Bigger: Piwi-Interacting RNAs (piRNAs) in Mammalian Testes," Genes Dev. 20, 1993 (2006)
S.T. Grivna et al., "MIWI Associates with Translational Machinery and PIWI-Interacting RNAs (piRNAs) in Regulating Spermatogenesis," Proc. Natl. Acad. Sci. U.S.A. 103, 13415 (2006)
Selected Labs
Gregory Hannon (Cold Spring Harbor Laboratory)
Thomas Tuschl (Rockefeller University)
David Bartel (MIT)
Robert Kingston (Massachusetts General Hospital/Harvard Medical School)
Haifan Lin (Yale Stem Cell Center)