当前位置：首页 >> 专题栏目 >> 中文摘要
2007年9月13日Nature中文摘要
 BIOX.CN  来源：生命经纬    2007年09月13日
封面故事：干旱生态系统植被大小分布规律
Positive feedbacks promote power-law clustering of Kalahari vegetation
/ Spatial vegetation patterns and imminent desertification in
Mediterranean arid ecosystems
干旱生态系统占地球土地面积的约40%，是20多亿人生活的家园，但它们在气候
变化和人类行动面前仍然很脆弱。Kéfi等人利用数值模型及来自西班牙、摩洛
哥和希腊的地中海生态系统的数据发现，植被斑块大小分布遵从一个“幂次法
则”。随着动物吃草对植被造成的压力的增大，斑块大小分布将偏离该“幂次法
则”，接近向荒漠条件过渡的状态。所以，斑块大小分布可能是荒漠化的一个有
用的预警。本期封面所示为西班牙Belchite的El Planerón自然保护区的一个干
旱景观（在封面照片的上部），下部所示为这一景观退化的情况（Letter p.
213）。在另一篇论文中，Scanlon等人用卫星影像表明，卡拉哈里盆地的树丛大
小分布也遵从一个无标度（scale-free）“幂次法则”。这种现象可以用与现有
树木附近的有利环境相关的正反馈来解释（Letter p. 209）。在一篇News &
Views文章中，Ricard Solé对这两篇论文都进行了讨论。封面照片：Sonia &
Micha?l Kéfi/ Yolanda Pueyo/ Santiago Beguería Portugués


微RNA在“组织器”形成中的作用（An early task for micro-RNAs）
MicroRNA control of Nodal signalling
“组织器”组织的生成是胚胎学上的一个核心事件。这一类细胞通常被称为
Spemann“组织器”，是由一个名为Nodal的变形生长因子β配体所产生的信号作
用中的一个不对称现象在发育中的胚胎的背侧诱导生成的。 人们对这一不对称
性知之甚少。现在，Martello等人发现，微RNA参与了这一过程。两个微RNA，即
miR-15 和miR-16，通过在Nodal受体Acvr2a的表达上产生一个背侧偏向来限制该
“组织器”的大小。微RNA是小的单链RNA分子，它们帮助调控基因表达，它们的
很多不同功能才刚刚开始被人们全面研究。这项新的研究工作表明，微RNA在胚
胎成形过程中的一个关键阶段发挥作用，它们是将β-catenin和Nodal信号作用
联系起来的一个环节。（Article p. 183）


在“红色巨星”光芒下的行星（Planets in the red）
A giant planet orbiting the 'extreme horizontal branch' star V 391
Pegasi
超过200个已知太阳系外行星中大多数绕与我们的太阳相似的主星序恒星运行。
当它们核心的氢耗尽时，它们将变成红色的巨型天体（“红色巨星”），能够轻
易到达并吞没比较靠里面的行星。在大约50亿年之后，太阳也将发生这种情况。
在此之后，地球的命运就是不确定的，但围绕一颗“后红色巨星”阶段的恒星运
转的一颗行星的发现表明，地球在那个时刻之后也许能够以某种形式存在下去。
该行星在距V 391 Pegasi大约1.7天文单位（AU）的轨道上运行。“红色巨星”
阶段的最大半径约为0.7 AU，该行星在主星序阶段的距离为1 AU。这表明，轨道
距离不到2 AU的行星（按照定义，这样的距离也包括太阳在内）能够经受住“红
色巨星”扩展而生存下来。（Letter p. 189; News & Views）


火星气候变化模型（A cool look at Mars）
Dynamics of ice ages on Mars
火星上日光照射的波动要比地球上大得多，这是由于其轴心相对于轨道平面的倾
斜度等天文因素变化较大。火星上的气候变化也相应地比地球上更强烈。现在，
Norbert Schorghofer建立了一个新的气候模型，该模型能够解释火星地表之下
冰层在40个主要冰期和500万年时间里的进退情况。这便解释了火星地表之下冰
层当前的分布。另外，从时间长而相对比较简单的火星冰层年龄地层学研究获得
的知识，应能帮助解释地球上更复杂的事件。（Letter p. 192）


Ps2分子被观测到（Positronium molecules）
The production of molecular positronium
多年前科学家就已经知道，一个电子和它的反粒子，即正电子，能够结合形成一
个亚稳态的、像氢原子一样的原子，被称为positronium (Ps)。据预测，两个Ps
原子可以结合形成di-positronium (Ps2)分子，但此前这种分子一直没有被无可
争议地观测到。当强正电子束照射进一个多孔二氧化硅薄膜时，Ps2就会在内部
的有孔表面上形成。采用一个更强的正电子源，也许有可能形成由Ps2分子构成
的一个玻色-爱因斯坦凝聚态，这对于了解物质的基本组成将具有重要意义，并
且也将成为制造湮灭伽玛射线激光器的道路上的一个里程碑。（Letter p. 195;
News & Views）


大气二氧化碳浓度与地球温度的确始终关联（Climate history）
Coupling of surface temperatures and atmospheric CO2 concentrations
during the Palaeozoic era
地球大气中高浓度的二氧化碳在遥远的地质年代是否始终与全球变暖联系在一
起？关于这个问题，地质学家有不同看法。对全球变暖持怀疑态度的人们总是能
抓住这一点。但一项新的研究工作为传统观点提供了进一步支持：大气二氧化碳
浓度和地球表面温度在地球的整个历史上一直是紧密联系在一起的。应用
“carbonate clumped isotope”“古温度计”（palaeothermometer）对古生代
海洋温度所做的分析表明，当大气二氧化碳浓度相对于目前水平较高时，地球温
度明显较高；而当大气二氧化碳浓度低到跟今天差不多时，地球温度也跟今天的
相似。（Letter p. 198）


地球大陆是脉冲式生长的（Taking the Earth’s pulse）
A link between large mantle melting events and continent growth seen
in osmium isotopes
实践证明，地球大陆壳的形成机制及形成时间（如它是在地球历史的早期一下子
形成的、是逐渐生长的、还是通过几次大幅度的脉冲式生长过程形成的）难以确
定。Pearson等人对大量锇合金颗粒进行了分析，以期确定熔岩从地幔中流出的
年代分布。他们发现，这些年代不是均匀分布的，而是集中在一些明显的时间段
中，这些时间段距今分别约12亿年、19亿年和27亿年，与大陆壳年龄的峰值相
合。这一结果支持认为大陆生长发生在与大规模地幔熔融事件相联系的脉冲中的
理论。（Letter p. 202）


石器时代事件与气候条件的关联（Under the weather）
Placing late Neanderthals in a climatic context
要将石器时代的事件与气候条件联系起来，因难以对距今大约21,000年（用放射
性碳测年方法测定的时间）前后的放射性碳测年记录进行校正、以及缺乏一个关
于气候事件年代的“总编年史”而受阻。但研究人员有一个办法来绕过这一问
题：放射碳年代可以通过优秀的Cariaco Basin深海记录与古气候记录联系起
来。这样，欧洲“尼安德特人”的消失就可以与已知的气候事件关联起来。将这
一分析应用于来自Gibralter的Gorham’s Cave的“尼安德特人”原始工具，研
究人员发现，“尼安德特人”在一次大规模的环境变迁发生之前可能一直在那里
繁衍生息。（Letter p. 206）


植物生长状况的预测（Plant growth prediction）
A general integrative model for scaling plant growth, carbon flux, and
functional trait spectra
能够利用植物的功能特征（如叶面积和质量、每株植物的叶子数量及生物质生产
的效率等）来在生态系统尺度上预测植物生长和碳通量的能力，在包括生态学、
种群生物学和全球变化研究等一系列领域都具有重要意义。Enquist等人建立了
一个模型，该模型能够进行这样的预测，为将预测工作从植物特征多样性扩大到
生态系统过程提供一个机制基础。（Letter p. 218）


“不朽链” 假说不适用于造血干细胞（The not-so-immortal strand）
Haematopoietic stem cells do not asymmetrically segregate chromosomes
or retain BrdU
1975年，John Cairns提出了“不朽链”（immortal strand）假说，将其作为成
年干细胞可用来减小突变积累的一个机制。这是通过选择性地保留含有“老”
DNA的染色体来做到的，对含有放射性标记或一个核苷类物质（如
bromodeoxyuridine (BrdU)）的DNA链所做的分析证明了这一点。本期Nature发
表了关于这一仍在争论的问题的一项新的研究工作。Kiel等人发现，“不朽链”
模型并不是干细胞的一个普遍性质，因为它并不适用于造血干细胞。这些细胞不
能通过保留BrdU标记来识别，并且在分裂过程中不能保留较老的DNA。（Letter
p. 238）


促动蛋白AvrPto的晶体结构被确定（Plant versus microbe）
The structural basis for activation of plant immunity by bacterial
effector protein AvrPto
很多微生物植物病原体都形成了促动蛋白（effector proteins），它们通过中
和宿主植物的防卫系统来增强毒性。针对这种情况，植物也形成了具有高度特异
性的抗性蛋白，它们能识别出促动蛋白，限制其感染——经常是通过诱导局部化
的细胞死亡来发挥这种作用的。现在，研究人员已经确定了这些促动蛋白中其中
一个的晶体结构，它就是来自Pseudomonas syringiae的AvrPto，与Pto激酶结合
在一起，后者能够让番茄产生对细菌性斑点病的抵抗力。它们之间相互作用的性
质表明，Pto可能是作为AvrPto毒性目标的一个模仿物而形成的。（Letter p.
243）


----------------------
NEWS AND VIEWS
----------------------
Extrasolar planets: The one that got away pp147 - 148
Hanging around a star that has passed through its red-giant phase
doesn't seem a likely place for a planet. But one planet apparently
managed to avoid being engulfed by its bloated star ― might others,
too?
Jonathan Fortney
doi:10.1038/449147a
http://www.nature.com/nature/journal/v449/n7159/full/449147a.html

Epigenetics: Perceptive enzymes pp148 - 149
Adding methyl groups to DNA is a way of regulating some genes and
genomic sequences. Structural analysis reveals that the enzyme complex
that mediates this process shows unexpected sequence specificity.
Anne C. Ferguson-Smith and John M. Greally
doi:10.1038/449148a
http://www.nature.com/nature/journal/v449/n7159/full/449148a.html

Chemistry: Molecular socks in a drawer pp149 - 151
Dynamic combinatorial chemistry is a deft way to identify the most
stable forms in a complex mixture of interconverting compounds. Even
more cunningly, it can also be used to sort related molecules by
crystallization.
Michael D. Ward
doi:10.1038/449149a
http://www.nature.com/nature/journal/v449/n7159/full/449149a.html

Ecology: Scaling laws in the drier pp151 - 153
The vegetation of arid ecosystems displays scale-free, self-organized
spatial patterns. Monitoring of such patterns could provide warning
signals of the occurrence of sudden shifts towards desert conditions.
Ricard Sole
doi:10.1038/449151a
http://www.nature.com/nature/journal/v449/n7159/full/449151a.html

Atomic physics: A whiff of antimatter soup pp153 - 155
A molecule consisting of two electrons and two anti-electrons is
similar to, but different from, the familiar hydrogen molecule H2. Its
creation heralds a new chapter in the formation of matter-antimatter
states.
Clifford M. Surko
doi:10.1038/449153a
http://www.nature.com/nature/journal/v449/n7159/full/449153a.html

50 & 100 Years Ago p153
doi:10.1038/449153b
http://www.nature.com/nature/journal/v449/n7159/full/449153b.html

Evolutionary genetics: You are what you ate p155
Sadaf Shadan
doi:10.1038/449155a
http://www.nature.com/nature/journal/v449/n7159/full/449155a.html

Obituary: Ernst Otto Fischer (1918-2007) p156
Organometallic chemist, and cosmopolitan Bavarian patriot.
Wolfgang A. Herrmann
doi:10.1038/449156a
http://www.nature.com/nature/journal/v449/n7159/full/449156a.html

----------------------
OUTLOOK
----------------------
NEGLECTED DISEASES
Neglected Diseases p157
David O'Connell
doi:10.1038/449157a
http://www.nature.com/nature/journal/v449/n7159/full/449157a.html

Lost in translation pp158 - 159
The culture of academia needs to change if scientists are to bridge
the gap between research and the development of drugs and vaccines for
neglected diseases in the developing world, says Declan Butler.
Declan Butler
doi:10.1038/449158a
http://www.nature.com/nature/journal/v449/n7159/full/449158a.html

A tough transition pp160 - 163
What is holding back biotechnology in the developing world? Peter A.
Singer and his colleagues listen to those on the ground.
Peter A. Singer et al.
doi:10.1038/449160a
http://www.nature.com/nature/journal/v449/n7159/full/449160a.html

The path to new medicines pp164 - 165
Governments must help accelerate the development of drugs needed to
treat infectious diseases in the developing world, say Benedicte
Callan and Iain Gillespie.
Benedicte Callan and Iain Gillespie
doi:10.1038/449164a
http://www.nature.com/nature/journal/v449/n7159/full/449164a.html

Mission possible pp166 - 169
One billion people worldwide suffer from tropical diseases. Andrew L.
Hopkins, Michael J. Witty and Solomon Nwaka explain how drug-discovery
networks might be scaled up to address the lack of treatments
cost-effectively.
Andrew L. Hopkins, Michael J. Witty and Solomon Nwaka
doi:10.1038/449166a
http://www.nature.com/nature/journal/v449/n7159/full/449166a.html

A prescription for drug delivery pp170 - 172
Improvements in basic infrastructure are the key to saving millions of
lives each year, say Julian Lob-Levyt and his colleagues.
Rebecca Affolder et al.
doi:10.1038/449170a
http://www.nature.com/nature/journal/v449/n7159/full/449170a.html

Patent sense pp174 - 175
Protecting intellectual property saves lives in the developing world,
argues Paul Herrling.
Paul Herrling
doi:10.1038/449174a
http://www.nature.com/nature/journal/v449/n7159/full/449174a.html

At what price? pp176 - 179
Differential pricing could make global medicines affordable in
developing countries. But drugs for diseases that have no market in
the developed world will require additional subsidies, says Patricia
M. Danzon.
Patricia M. Danzon
doi:10.1038/449176a
http://www.nature.com/nature/journal/v449/n7159/full/449176a.html

The road to recovery pp180 - 182
Brazil urgently needs to improve infrastructure for generating
pharmaceuticals to alleviate the plight of its poor and marginalized
populations, say Carlos M. Morel et al.
Carlos M. Morel et al.
doi:10.1038/449180a
http://www.nature.com/nature/journal/v449/n7159/full/449180a.html

----------------------
ARTICLES
----------------------
MicroRNA control of Nodal signalling pp183 - 188
Generation of the organizer tissue is induced on the dorsal side of
the developing embryo by an asymmetry in Nodal signalling, which is
only sufficiently high dorsally to induce organizer-specific gene
expression. Now, through the identification of a microRNA (miR-15 and
miR-16) that targets the Nodal receptor, microRNA is shown to have a
role in this process.
Graziano Martello et al.
doi:10.1038/nature06100
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06100.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06100.html

----------------------
LETTERS
----------------------
A giant planet orbiting the 'extreme horizontal branch' star V391
Pegasi pp189 - 191
The discovery of a planet orbiting the post-red-giant phase star V 391
Pegasi at a distance of about 1.7 astronomical units (AU) is reported.
The maximum radius of the red giant phase was ～0.7 AU, whereas the
distance of the planet during main sequence phase was ～1 AU. This
demonstrates that planets with orbital distances < 2 AU can survive
the red giant expansion.
R. Silvotti et al.
doi:10.1038/nature06143
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06143.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06143.html

Dynamics of ice ages on Mars pp192 - 194
Numerical simulation and modelling of the retreat and growth of ground
ice on Mars demonstrates how the subsurface ice sheets could have
evolved and ended up in the state we see them today, and also reveals
that 40 major ice ages occurred on Mars over the past 5 million years
Norbert Schorghofer
doi:10.1038/nature06082
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06082.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06082.html

The production of molecular positronium pp195 - 197
When intense positron bursts are implanted into a thin film of porous
silica, di-positronium (Ps2) is created on the internal pore surfaces,
providing experimental proof of the existence of the molecule. Using a
more intense positron source, it may be possible to form a
Bose-Einstein condensate of Psf2 molecules, which would be of
significant fundamental interest and a milestone on the path to
produce an annihilation gamma-ray laser.
D. B. Cassidy and A. P. Mills, Jr
doi:10.1038/nature06094
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06094.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06094.html

Coupling of surface temperatures and atmospheric CO2 concentrations
during the Palaeozoic era pp198 - 201
Tropical sea surface temperatures during the Palaeozoic era were
reconstructed from fossil shells using the 'carbonate clumped isotope'
method, which, unlike the oxygen isotope method, does not require
independent estimates of the isotopic composition of seawater.
Estimates indicate that carbon dioxide concentrations and surface
temperatures were closely coupled during the Palaeozoic era,
supporting the view that variations in atmospheric carbon dioxide
concentration led to significant variations in global temperature.
Rosemarie E. Came et al.
doi:10.1038/nature06085
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06085.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06085.html

A link between large mantle melting events and continent growth seen
in osmium isotopes pp202 - 205
Large numbers of osmium alloy grains are analysed to quantify the
distribution of ages at which melt was extracted from the Earth's
mantle. It is found that the ages are not evenly distributed but
cluster in distinct periods, around 1.2, 1.9 and 2.7 billion years,
coincident with peaks in the ages of continental crust, lending strong
support to pulsed models of continental growth via large-scale mantle
melting events.
D. G. Pearson, S. W. Parman and G. M. Nowell
doi:10.1038/nature06122
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06122.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06122.html

Placing late Neanderthals in a climatic context pp206 - 208
Attempts to place Palaeolithic events in climatic context are hampered
by the difficulty of calibrating the radiocarbon calendar beyond
around 21,000 radiocarbon years ago, and the absence of a 'master'
calendar chronology for climate events. But this is circumvented by
relating radiocarbon years to the paleoclimatic record through the
excellent Cariaco Basin deep-sea record. In this way it is possible to
relate the disappearance of Neanderthals in Europe to known climatic
events.
P. C. Tzedakis, K. A. Hughen, I. Cacho and K. Harvati
doi:10.1038/nature06117
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06117.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06117.html

Positive feedbacks promote power-law clustering of Kalahari
vegetation pp209 - 212
It is shown that clusters of tree canopies within Kalahari landscape
in southern Africa lack characteristic size, with the size
distributions following power laws. Model results indicate that this
apparent self-organized behaviour can be explained by positive
feedbacks that operate in this water-limited ecosystem as a result of
preferential environments formed within the vicinity of existing
trees.
Todd M. Scanlon, Kelly K. Caylor, Simon A. Levin and Ignacio
Rodriguez-Iturbe
doi:10.1038/nature06060
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06060.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06060.html

Spatial vegetation patterns and imminent desertification in
Mediterranean arid ecosystems pp213 - 217
This paper describes and models the effect of grazing on vegetation
patchiness in three arid Mediterranean ecosystems. The patch size
distribution of the vegetation in these ecosystems follows a power
law, which can be explained by invoking local positive interactions
among plants. Deviations from power laws occur when grazing pressure
is high, and may be a harbinger of imminent desertification.
Sonia Kefi et al.
doi:10.1038/nature06111
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06111.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06111.html

A general integrative model for scaling plant growth, carbon flux, and
functional trait spectra pp218 - 222
A generalized trait-based model is derived to predict plant growth and
hence the flux of carbon within and across plants. The model provides
a theoretical basis for the merging of metabolic scaling theory with
recent work on functional trait spectra, in turn helping to understand
the integration of functional traits within plant phenotypes.
Brian J. Enquist et al.
doi:10.1038/nature06061
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06061.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06061.html

Dscam diversity is essential for neuronal wiring and
self-recognition pp223 - 227
Use of a novel approach to generate mosaic animals shows that Down
syndrome cell adhesion molecules (Dscam) diversity plays a crucial
role in providing neurons in the Drosophila central nervous system
with the ability to distinguish between self and non-self, which is
essential to patterning neural circuits.
Daisuke Hattori et al.
doi:10.1038/nature06099
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06099.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06099.html

Glucose sensing by POMC neurons regulates glucose homeostasis and is
impaired in obesity pp228 - 232
Mice that cannot sense glucose with their pro-opiomelanocortin (POMC
neurons) develop glucose intolerance, demonstrating that glucose
sensing in neurons plays an important role in responding to a systemic
glucose load. It is also shown that in mice with obesity-induced type
2 diabetes, glucose-sensing by POMC neurons is defective.
Laura E. Parton et al.
doi:10.1038/nature06098
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06098.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06098.html

The structural basis of yeast prion strain variants pp233 - 237
A comprehensive structural analysis of the complete and unmodified
Sup35 prion domain in two distinct infectious conformations is
presented. A variety of techniques is used to provide structural
details of these two prion conformations, one weakly and one strongly
propagating strain. The data show that the fibril conformation of both
strains share a common amyloid-like core, comprising the
glutamine/asparagine rich first 40 residues.In the weaker strain this
stable structure is dramatically expanded to 70 amino acids.
Brandon H. Toyama, Mark J. S. Kelly, John D. Gross and Jonathan S.
Weissman
doi:10.1038/nature06108
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06108.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06108.html

Haematopoietic stem cells do not asymmetrically segregate chromosomes
or retain BrdU pp238 - 242
The 'immortal strand' hypothesis has been proposed as a mechanism by
which adult stem cells minimize accumulation of mutations. This is
achieved by selectively retain chromosomes containing 'old' DNA, as
shown by the analysis of the DNA strands that incorporated radioactive
label or a nucleotide analogue such as bromodeoxyuridine. A new
important contribution to this ongoing debate shows that 'the immortal
strand' model does not apply to haematopoietic stem cells and BrdU
label retention should not be viewed as a fundamental characteristic
of stem cells.
Mark J. Kiel et al.
doi:10.1038/nature06115
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06115.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06115.html

The structural basis for activation of plant immunity by bacterial
effector protein AvrPto pp243 - 247
Plant pathogens produce effector proteins that enhance virulence in
susceptible plants, but trigger an immune response in resistant
plants. This hypersensitive response is elicited through the
interaction between the bacterial effector and the appropriate host
resistance protein. This study describes the first crystal structure
of a pathogen effector (AvrPto) bound to its cognate host protein
(Pto).
Weiman Xing et al.
doi:10.1038/nature06109
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06109.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06109.html

Structure of Dnmt3a bound to Dnmt3L suggests a model for de novo DNA
methylation pp248 - 251
A crystal structure of a complex between the DNA methyltransferase
regulatory factor Dnmt3L and the catalytic domain of Dnmt3a leads to a
model being proposed for the preferential methylation of DNA on
maternally imprinted genes.
Da Jia et al.
doi:10.1038/nature06146
Abstract:
http://www.nature.com/nature/journal/v449/n7159/abs/nature06146.html
Article:
http://www.nature.com/nature/journal/v449/n7159/full/nature06146.html
 
    
 


【发表评论】 【进入论坛】【关闭页面】
相关文章