Nature：杂交优势的机制基础

多倍性（或称整基因组复制）是植物中常见的一种演化创新。几种主要作物（包括小麦、棉花和油菜）是异源多倍体，含有两个或多个趋异的基因组，而且一些植物也以种内和种间杂交体的形式存在。这样的植物会有旺盛的生长现象。
美国得克萨斯大学与中国农业大学的研究小组通过对两种拟南芥植物（Arabidopsis thaliana 和 A. arenosa.）的杂交体所做的一项研究为了解杂交体生长能力增强的机制基础提供了线索。研究表明，生物节律时钟的表观基因调制在异源多倍体中调节光合作用通道及淀粉代谢通道中的基因表达。因此，它们比其父辈积累更多叶绿素，产生更多淀粉，而且长得更大。所以，杂交体和异源多倍体植物似乎能通过可逆调整生物节律时钟调控因子而从生理及代谢通道的控制中获得优势，以更好利用白天的时间。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 457, 327-331 (15 January 2009) doi:10.1038/nature07523
Altered circadian rhythms regulate growth vigour in hybrids and allopolyploids
Zhongfu Ni1,6,7, Eun-Deok Kim1,6, Misook Ha1,2,3, Erika Lackey1, Jianxin Liu1, Yirong Zhang1,7, Qixin Sun5 & Z. Jeffrey Chen1,2,3,4
1 Section of Molecular Cell and Developmental Biology,2 Institute for Cellular and Molecular Biology,3 Center for Computational Biology and Bioinformatics, and,4 Section of Integrative Biology, The University of Texas at Austin, One University Station, A-4800, Austin, Texas 78712, USA5 Department of Plant Genetics and Breeding, China Agricultural University, Yuanmingyuan Xilu No. 2, Beijing, 100094, China6 These authors contributed equally to this work.
Segregating hybrids and stable allopolyploids display morphological vigour1, 2, 3, and Arabidopsis allotetraploids are larger than the parents Arabidopsis thaliana and Arabidopsis arenosa 1, 4—the mechanisms for this are unknown. Circadian clocks mediate metabolic pathways and increase fitness in animals and plants5, 6, 7, 8. Here we report that epigenetic modifications of the circadian clock genes CIRCADIAN CLOCK ASSOCIATED 1 (CCA1) and LATE ELONGATED HYPOCOTYL (LHY)9, 10, 11 and their reciprocal regulators TIMING OF CAB EXPRESSION 1 (TOC1) and GIGANTEA (GI)10, 12, 13 mediate expression changes in downstream genes and pathways. During the day, epigenetic repression of CCA1 and LHY induced the expression of TOC1, GI and downstream genes containing evening elements14 in chlorophyll and starch metabolic pathways in allotetraploids and F1 hybrids, which produced more chlorophyll and starch than the parents in the same environment. Mutations in cca1 and cca1 lhy and the daily repression of cca1 by RNA interference (RNAi) in TOC1::cca1(RNAi) transgenic plants increased the expression of downstream genes and increased chlorophyll and starch content, whereas constitutively expressing CCA1 or ectopically expressing TOC1::CCA1 had the opposite effect. The causal effects of CCA1 on output traits suggest that hybrids and allopolyploids gain advantages from the control of circadian-mediated physiological and metabolic pathways, leading to growth vigour and increased biomass.

The Plant Journal：水稻磷酸盐转运蛋白基因研究

南京农业大学的研究人员通过转基因手段和生物化学及生物物理方法，研究揭示了水稻中两个重要的磷酸盐转运蛋白基因的作用及其动力学特征。相关成果近日在国际植物学著名学术期刊《植物学杂志》（The Plant Journal）在线发表。
领导这一研究的是南京农业大学的徐国华教授，其于2000年在以色列耶路撒冷希伯来大学（The Hebrew University of Jerusalem）获得博士学位，曾在以色列国家科学院（WEIZMANN）进行博士后研究。徐国华主持的作物养分资源高效利用的生物学途径课题得到了 “973”项目资助。
磷是植物生长发育所必需的三大营养元素之一。磷素被植物吸收和“运输”依赖于植物体内各种各样的磷素的“挑夫”———磷酸盐转运蛋白。但不同的“挑夫”是怎样工作的，目前植物营养学界一直在探索。研究人员通过转基因手段和生物化学及生物物理方法，研究揭示了水稻中两个重要的磷酸盐转运蛋白基因的作用及其动力学特征。
据论文第一作者、南京农大在校博士生艾鹏慧介绍，由于土壤中的有效磷含量很低，植物自身就会通过改变根的形态和结构来产生大量根毛、侧根、排根以及分泌有机酸、磷酸酶等方式来尽可能地提高土壤中磷的有效性。这些磷素的吸收和利用都要借助于植物体内的“磷酸盐转运蛋白”来完成。根据对磷的吸收能力，学界把磷酸盐转运蛋白分为高亲和力转运蛋白与低亲和力转运蛋白。（生物谷Bioon.com）
生物谷推荐原始出处：
The Plant Journal，doi: 10.1111/j.1365-313X.2008.03726.x，Penghui Ai，Guohua Xu
Two rice phosphate transporters, OsPht1;2 and OsPht1;6, have different functions and kinetic properties in uptake and translocation
Penghui Ai 1, , Shubin Sun 1, , Jianning Zhao 1, , Xiaorong Fan 1 , Weijie Xin 1 , Qiang Guo 1 , Ling Yu 2 , Qirong Shen 1 , Ping Wu 3 , Anthony J. Miller 4 and Guohua Xu 1,*
1 State Key Laboratory of Crop Genetics and Germplasm Enhancement, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China , 2 The Center for Cell and Molecular Signaling, School of Medicine, Emory University, 30322 USA , 3 State Key Laboratory of Plant Physiology and Biochemistry, College of Life Science, Zhejiang University, Hangzhou 310029, China , and 4 Centre for Soils and Ecosystem Function, Rothamsted Research, Harpenden, Hertfordshire AL5 2JQ, UK
Plant phosphate (Pi) transporters mediate the uptake and translocation of this nutrient within plants. A total of 13 sequences in the rice (Oryza sativa) genome can be identified as belonging to the Pi transporter (Pht1) family. Here, we report on the expression patterns, biological properties and the physiological roles of two members of the family: OsPht1;2 (OsPT2) and OsPht1;6 (OsPT6). Expression of both genes increased significantly under Pi deprivation in roots and shoots. By using transgenic rice plants expressing the GUS reporter gene, driven by their promoters, we detected that OsPT2 was localized exclusively in the stele of primary and lateral roots, whereas OsPT6 was expressed in both epidermal and cortical cells of the younger primary and lateral roots. OsPT6, but not OsPT2, was able to complement a yeast Pi uptake mutant in the high-affinity concentration range. Xenopus oocytes injected with OsPT2 mRNA showed increased Pi accumulation and a Pi-elicited depolarization of the cell membrane electrical potential, when supplied with mM external concentrations. Both results show that OsPT2 mediated the uptake of Pi in oocytes. In transgenic rice, the knock-down of either OsPT2 or OsPT6 expression by RNA interference significantly decreased both the uptake and the long-distance transport of Pi from roots to shoots. Taken together, these data suggest OsPT6 plays a broad role in Pi uptake and translocation throughout the plant, whereas OsPT2 is a low-affinity Pi transporter, and functions in translocation of the stored Pi in the plant.

Nature：硅藻中发现铁蛋白

专题：Nature报道 非血红素蛋白“铁蛋白”被很多植物、动物和微生物用来以一种非毒性可溶形式存储铁，这种形式在需要时容易被利用。 美国和加拿大的研究人员最近在两种硅藻中发现了，“铁蛋白”。它们分别是Pseudo-nitzschia 和 Fragilariopsis。这两种硅藻主导由以自然方式和人工方式为海洋中补充铁所诱导的浮游植物繁盛现象。这是在“金黄藻菌鞭毛菌界”（Stramenopila）任何一个成员中关于“铁蛋白”的首次报告。 “金黄藻菌鞭毛菌界”是真核生物的一个分支，包括很多浮游植物，如单细胞藻类、硅藻和大型藻类等。




蛋白质结合铁原子示意图，图中粉色为铁原子
系统发育分析表明，“铁蛋白”是通过侧向基因转移在硅藻的这一小类别中出现的，它也许是它们在铁供应为初级生产力限制因素的30-40%的海洋中能够成功生存的关键。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 457, 467-470 (22 January 2009) doi:10.1038/nature07539
Ferritin is used for iron storage in bloom-forming marine pennate diatoms
Adrian Marchetti1,4, Micaela S. Parker1,4, Lauren P. Moccia2, Ellen O. Lin1, Angele L. Arrieta3, Francois Ribalet1, Michael E. P. Murphy3, Maria T. Maldonado2 & E. Virginia Armbrust1
1 School of Oceanography, University of Washington, Box 357940, Seattle, Washington 98195, USA 2 Department of Earth and Ocean Sciences, University of British Columbia, 6270 University Boulevard, Vancouver, British Columbia V6T 1Z4, Canada 3 Department of Microbiology and Immunology, University of British Columbia, 2350 Health Sciences Mall, Vancouver, British Columbia V6T 1Z3, Canada 4 These authors contributed equally to this work.
Primary productivity in 30–40% of the world's oceans is limited by availability of the micronutrient iron1, 2. Regions with chronically low iron concentrations are sporadically pulsed with new iron inputs by way of dust3 or lateral advection from continental margins4. Addition of iron to surface waters in these areas induces massive phytoplankton blooms dominated primarily by pennate diatoms5, 6. Here we provide evidence that the bloom-forming pennate diatoms Pseudo-nitzschia and Fragilariopsis use the iron-concentrating protein, ferritin, to safely store iron. Ferritin has not been reported previously in any member of the Stramenopiles, a diverse eukaryotic lineage that includes unicellular algae, macroalgae and plant parasites. Phylogenetic analyses suggest that ferritin may have arisen in this small subset of diatoms through a lateral gene transfer. The crystal structure and functional assays of recombinant ferritin derived from Pseudo-nitzschia multiseries reveal a maxi-ferritin that exhibits ferroxidase activity and binds iron. The protein is predicted to be targeted to the chloroplast to control the distribution and storage of iron for proper functioning of the photosynthetic machinery. Abundance of Pseudo-nitzschia ferritin transcripts is regulated by iron nutritional status, and is closely tied to the loss and recovery of photosynthetic competence. Enhanced iron storage with ferritin allows the oceanic diatom Pseudo-nitzschia granii to undergo several more cell divisions in the absence of iron than the comparably sized, oceanic centric diatom Thalassiosira oceanica. Ferritin in pennate diatoms probably contributes to their success in chronically low-iron regions that receive intermittent iron inputs, and provides an explanation for the importance of these organisms in regulating oceanic CO2 over geological timescales7, 8.

Science：揭示骡子为什么不能繁殖

只有正确的组氨酸基因才能够让水芹种子发育。
（图片提供:Olivier Loudet/INRA）
大自然自有一套规律能够保持物种的独立：大多数杂种有机体——例如骡子和狮虎——都是不能繁殖的。然而隐藏在这种现象背后的机制却一直没有搞清，如今，科学家相信，他们已经抓住了导致这一切的遗传因素。
为更多地了解是什么原因导致物种分离，以及新物种是如何形成的，巴黎市法国国立农业研究所的生物学家Olivier Loudet将目光投向了水芹(Arabidopsis thaliana)，这是一种来自于十字花科的野草。研究人员在2000年对全部的水芹基因组进行了测序，并进行了相关的遗传分析工作。同时，由于有许多种群在世界各地生长，从而使水芹具有丰富的遗传多样性。
Loudet和同事抽取了两个水芹种群样本——它们分别来自波兰和大西洋中部的佛得角群岛。研究人员随即注意到一个细微的遗传差异：佛得角群岛水芹的5号染色体上的一个与组氨酸有关的基因的一个副本被删除了，同时它在波兰水芹的1号染色体中也根本没有表达。当这两种遗传性变型通过杂交结合在一起后，11%的晶胚死亡。其他杂交植物的根则明显短于正常植物的根系，并伴有其他疾病。研究人员认为，这两种结果都与组氨酸的供给不足有关。研究人员在最新出版的美国《科学》杂志上报告了这一研究成果。
由其他的30个水芹种群产生的杂交植物有1/4是无法繁殖的。Loudet认为，这意味着单一基因的进化能够在一个物种中迅速导致差异。
美国布卢明顿市印第安纳大学的进化遗传学家Leonie Moyle认为，这一研究结果非常“令人兴奋”，这是因为它发现了相同物种的“血统”在遗传上存在不相容的第一个明显例证。（生物谷Bioon.com）
生物谷推荐原始出处：
Science，Vol. 323. no. 5914, pp. 623 - 626，David Bikard，Olivier Loudet
Divergent Evolution of Duplicate Genes Leads to Genetic Incompatibilities Within A. thaliana
David Bikard,1 Dhaval Patel,2 Claire Le Metté,1 Veronica Giorgi,1 Christine Camilleri,1 Malcolm J. Bennett,2 Olivier Loudet1*
Genetic incompatibilities resulting from interactions between two loci represent a potential source of postzygotic barriers and may be an important factor in evolution when they impair the outcome of interspecific crosses. We show that, in crosses between strains of the plant Arabidopsis thaliana, loci interact epistatically, controlling a recessive embryo lethality. This interaction is explained by divergent evolution occurring among paralogs of an essential duplicate gene, for which the functional copy is not located at the same locus in different accessions. These paralogs demonstrate genetic heterogeneity in their respective evolutionary trajectories, which results in widespread incompatibility among strains. Our data suggest that these passive mechanisms, gene duplication and extinction, could represent an important source of genetic incompatibilities across all taxa.
1 Genetics and Plant Breeding, INRA, SGAP UR254, F-78026 Versailles, France.2 Centre for Plant Integrative Biology, Division of Plant Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.

Nature：烟曲霉可进行有性生殖

专题：Nature报道
烟曲霉（Aspergillus fumigatus）是一种重要的致病菌，烟曲霉进入人体后，能引起多重变应性和侵入性疾病，支气管肺病属于侵入性曲霉病最普通的临床表现。属于子囊菌类，它能够产生菌丝体。通过从菌丝体释放出来的无性孢子进行传播，这种孢子是一种极为坚固、生命力持久的芽胞。

（生物谷注：烟曲霉闭囊壳电镜照片）
尽管越来越多的证据表明，“烟曲霉”存在重组和基因流动，但此前在该物种中只观察到无性生殖。现在，在该真菌被定性145年之后，它被发现是有性生殖的。本期Nature报告了有两个互补交配类型的分离菌种。这一研究的意义包括，人们有可能进行经典的遗传分析，而这种分析又能帮助研究这种真菌致病作用及对抗菌剂产生抵抗力的遗传基础。（生物谷Bioon.com）
生物谷推荐原始出处：
Nature 457, 471-474 (22 January 2009) doi:10.1038/nature07528
Discovery of a sexual cycle in the opportunistic fungal pathogen Aspergillus fumigatus
Céline M. O'Gorman1,2, Hubert T. Fuller1 & Paul S. Dyer2
1 UCD School of Biology and Environmental Science, University College Dublin, Belfield, Dublin 4, Ireland2 School of Biology, University of Nottingham, University Park, Nottingham NG7 2RD, UK
Aspergillus fumigatus is a saprotrophic fungus whose spores are ubiquitous in the atmosphere1. It is also an opportunistic human pathogen in immunocompromised individuals, causing potentially lethal invasive infections2, 3, and is associated with severe asthma and sinusitis4. The species is only known to reproduce by asexual means5, but there has been accumulating evidence for recombination and gene flow from population genetic studies5, 6, 7, 8, genome analysis9, 10, the presence of mating-type genes8, 10 and expression of sex-related genes8 in the fungus. Here we show that A. fumigatus possesses a fully functional sexual reproductive cycle that leads to the production of cleistothecia and ascospores, and the teleomorph Neosartorya fumigata is described. The species has a heterothallic breeding system; isolates of complementary mating types are required for sex to occur. We demonstrate increased genotypic variation resulting from recombination between mating type and DNA fingerprint markers in ascospore progeny from an Irish environmental subpopulation. The ability of A. fumigatus to engage in sexual reproduction is highly significant in understanding the biology and evolution of the species. The presence of a sexual cycle provides an invaluable tool for classical genetic analyses and will facilitate research into the genetic basis of pathogenicity and fungicide resistance in A. fumigatus, with the aim of improving methods for the control of aspergillosis. These results also yield insights into the potential for sexual reproduction in other supposedly 'asexual' fungi.

Nature Genetics：发现3个与儿童肥胖症相关的基因变异

一个国际科研小组在最新一期英国《自然·遗传学》杂志上报告说，他们新发现3个与儿童肥胖症相关的基因变异，这将有助于医学研究人员预测乃至治疗儿童肥胖症。
来自法国国家科研中心、英国伦敦帝国理工学院等机构的研究人员介绍说，他们在这项长达10年的研究中，对上千名6岁以下肥胖儿童及一些成年肥胖症患者进行了全基因组关联分析，这些成年研究对象都是从儿童期或青春期就开始出现肥胖症状的。
研究人员将他们的基因信息与同年龄段正常体重者的基因信息对比，结果识别出3个以前从未发现的基因变异，而50％的儿童肥胖症患者都与这3个基因变异有关。
在这3个基因变异中，与儿童肥胖症以及成年肥胖症关联最密切的一个，位于PTER基因附近，研究人员目前尚不清楚该基因的功能。他们估计，儿童肥胖症中有三分之一都可归结到这个基因变异上，成年肥胖症中也有大约五分之一与它有关。
第二个基因变异位于NPC1基因中。此前以老鼠为对象的研究已经表明，这个基因与食欲有关。研究人员估计，儿童肥胖症中有十分之一与这一基因变异相关。
第三个基因变异位于MAF基因附近。该基因负责控制胰岛素、胰高血糖素及胰高血糖素样肽的产生，这些激素和肽在人体葡萄糖和碳水化合物的代谢中都扮演关键角色。儿童肥胖症中大约有6％的病例与这个基因变异有关。
研究小组在报告中说，下一步，他们将进行更深入的研究，以确认这3个基因是否独立发挥作用。他们表示，新发现及以往在该领域的研究成果，将有助于医学界开发出基因工具，预测哪些儿童是“高危”肥胖儿，并提前予以干预，避免儿童出现肥胖症状。(生物谷Bioon.com）
生物谷推荐原始出处：
Nature Genetics Published online: 18 January 2009 doi:10.1038/ng.301
Genome-wide association study for early-onset and morbid adult obesity identifies three new risk loci in European populations
David Meyre1, Jér?me Delplanque1, Jean-Claude Chèvre1, Cécile Lecoeur1, Stéphane Lobbens1, Sophie Gallina1, Emmanuelle Durand1, Vincent Vatin1, Franck Degraeve1, Christine Proen?a1, Stefan Gaget1, Antje K?rner2, Peter Kovacs3, Wieland Kiess2, Jean Tichet4, Michel Marre5, Anna-Liisa Hartikainen6, Fritz Horber7, Natascha Potoczna7, Serge Hercberg8, Claire Levy-Marchal9, Fran?ois Pattou10, Barbara Heude11, Maithé Tauber12, Mark I McCarthy13,14,15, Alexandra I F Blakemore16, Alexandre Montpetit17, Constantin Polychronakos17, Jacques Weill18, Lachlan J M Coin19, Julian Asher16, Paul Elliott19, Marjo-Riitta J?rvelin19,20, Sophie Visvikis-Siest21, Beverley Balkau11, Rob Sladek17, David Balding19, Andrew Walley16, Christian Dina1 & Philippe Froguel1,16
We analyzed genome-wide association data from 1,380 Europeans with early-onset and morbid adult obesity and 1,416 age-matched normal-weight controls. Thirty-eight markers showing strong association were further evaluated in 14,186 European subjects. In addition to FTO and MC4R, we detected significant association of obesity with three new risk loci in NPC1 (endosomal/lysosomal Niemann-Pick C1 gene, P = 2.9 10-7), near MAF (encoding the transcription factor c-MAF, P = 3.8 10-13) and near PTER (phosphotriesterase-related gene, P = 2.1 10-7).
1 CNRS 8090-Institute of Biology, Pasteur Institute, 59000 Lille, France.2 University Hospital for Children & Adolescents, University of Leipzig, 04103 Leipzig, Germany.3 Interdisciplinary Centre for Clinical Research, University of Leipzig, 04103 Leipzig, Germany.4 Institut Inter Régional pour la Santé, 37521 La Riche, France.5 Department of Endocrinology, Diabetology, Nutrition, Bichat-Claude Bernard University Hospital, Assistance Publique des H?pitaux de Paris, 75018 Paris, France, and Institut National de la Santé et de la Recherche Médicale U695, 6 Université Paris 7, 75007 Paris, France.7 Department of Clinical Sciences/ Obstetrics and Gynecology, University of Oulu, University of Oulu, 90014 Oulu, Finland.8 Klinik Lindberg, 8400 Winterthur, and University of Berne, 3012 Berne, Switzerland.9 Unité Mixte de Recherche U557 Institut National de la Santé et de la Recherche Médicale, U1125 Institut National de la 10 Recherche Agronomique, Conservatoire National des arts et Métiers, Université Paris 13, Centre de Recherches en 11 Nutrition Humaine Ile de France, F-93017 Bobigny, France.12 Institut National de la Santé et de la Recherche Médicale, U690, Paris, FR-75019, France and Université Paris Diderot, Paris, FR-75205 cedex 13, France.13 Institut National de la Santé et de la Recherche Médicale U859, Centre Hospitalier Régional Universitaire de Lille, 14 Lille North of France University, 59000 Lille France.15 Institut National de la Santé et de la Recherche Médicale U780, Villejuif, F-94807; University Paris-Sud, Orsay, F-91405, France.16 Institut National de la Santé et de la Recherche Médicale U563, Children's Hospital, Centre Hospitalier Universitaire 31000 Toulouse, France.17 Oxford Centre for Diabetes, Endocrinology & Metabolism, University of Oxford, OX3 7LJ Oxford, UK.18 Wellcome Trust Centre for Human Genetics, University of Oxford, OX3 Oxford, UK.19 Oxford National Institute for Health Research Biomedical Research Centre, OX3 Oxford, UK.20 Section of Genomic Medicine, Hammersmith Hospital, Imperial College London, W12 0HS London, UK.21 McGill University and Genome Quebec Innovation Centre, H3A 1A Montreal, Canada.22 Pediatric Endocrine Unit, Jeanne de Flandre Hospital, 59000 Lille, France.23 Department of Epidemiology and Public Health, Imperial College London, WC1E 6BT London UK.24 Institute of Health Sciences, University of Oulu, Department of Child and Adolescent Health, National Public Health 25 Institute, Biocenter Oulu, University of Oulu, 90014 Oulu, Finland.26 Institut National de la Santé et de la Recherche Médicale "Cardiovascular Genetics" team, Centre D'investigation Clinique 54000 Nancy, France.

PLoS Genetics：家猪皮毛的花纹和斑点系人为改变

来自瑞典Linderod的黑点品种仔猪，MC1R基因通过连续两次变异，生成了黑色斑点。
为什么我们常常能看到家猪的皮毛上会有奇怪的斑点和各种颜色，而野猪却很少出现这样的情况？据近日国外研究表示，家畜皮毛出现怪异颜色和花纹，这之中免不了人类的“功劳”，很早以前的农民有可能为了娱乐和满足自己的好奇心，人为改变了家畜的遗传基因。
研究人员表示，早在几千年前，人类就曾经人为促使动物基因突变，以“制造”出拥有不寻常颜色、花纹和斑点的动物。
这项研究将野猪和家猪进行了对比，而其研究的结论同样可以解释包括牛和狗等家养动物的皮毛出现色斑的原因，以及已经持续了几千年之久的演变过程。
科学家称，早在几千年前，农民们就已经学会了选育毛皮上出现与众不同图案家畜的技巧。选育过程中的各种改变会对黑素皮质素受体1 （MC1R ）——一种可以控制动物毛表颜色的基因——带来很大的影响。
而早期农民们所做的这种选育试验成果可以在我们现在的动物身上清楚的看到——现在的家畜毛表有着与它们肤色均匀的野生祖先们明显不同的斑点、条纹和颜色。
近日，一项关于欧洲和亚洲野猪家猪对比研究的报告在《PLoS遗传学》在线杂志上发表，这份研究报告向人们展示了家猪的遗传基因改造在几千年来是如何进行的。
科学家表示，人为改变家畜毛表颜色的一个可能原因在于有意改变动物原有的伪装保护色，这样便于农民一眼就能看到自己的家畜。
另一种可能的原因是，农民们为了通过改变家畜毛色和图案来给它们作“标记”，使其与它们的祖先和野生同类区别开来。当然，农民们这么做也有可能只是为了好玩和满足一下好奇心。
来自达拉谟大学的科学家格雷格·拉瑞森博士称：“第三种可能是，类似当今人类所为，早期的农民为了自娱或是增加生物的新颖性和多样性而人为培育出不同花色皮毛的家畜。”
研究人员发现，其实野猪和家猪出现DNA突变都是很常见的现象。不同的是，在野猪的DNA突变过程中MC1R基因并没有改变，即使是DNA突变，它们仍然保留了原有的高伪装度黑棕色“制服”。因为如果毛皮颜色改变，会令野猪更容易被捕食者发现，受到攻击的几率大大增加。所以，即使有MC1R基因发生改变的野猪，也很快就被捕食者“消灭”了。
形成明显对比的是，科学家在研究中发现，在接受观测的DNA突变家猪中几乎所有对象的MC1R基因都发生了变化。
而在一些家猪身上甚至能发现MC1R基因三个层次的变化，这也表明了最初的改变已经存在了很长的时间。
这项研究的结果这也成为了证明几千年来农民对家畜进行了积极而永久性的基因突变“促进工作”，以导致家畜的毛表出现各种颜色改变。
拉瑞森博士表示：“资料显示，早在5千年前，美索不达米亚就出现了不同颜色的家畜，而我们的研究结果表明在那之前就已经出现了黑白斑点的宠物和家畜。从某种意义上说，这些让家畜身着‘花衣’的早期农民们和热衷于给爱犬染毛扮靓的现代人没多大区别。而这项研究结果也表明，早在数千年前，人类就已经对创造新奇事物充满了热情。”（生物谷Bioon.com）
生物谷推荐原始出处：
PLoS Genet 5(1): e1000341. doi:10.1371/journal.pgen.1000341
Contrasting Mode of Evolution at a Coat Color Locus in Wild and Domestic Pigs
Meiying Fang1,2, Greger Larson3, Helena Soares Ribeiro1, Ning Li4, Leif Andersson1,3
1 Department of Animal Breeding and Genetics, Swedish University of Agricultural Sciences, Uppsala, Sweden, 2 College of Animal Science and Technology, China Agricultural University, Beijing, China, 3 Department of Medical Biochemistry and Microbiology, Uppsala University, Uppsala, Sweden, 4 State Key Laboratory for Agrobiotechnology, China Agricultural University, Beijing, China
Despite having only begun ~10,000 years ago, the process of domestication has resulted in a degree of phenotypic variation within individual species normally associated with much deeper evolutionary time scales. Though many variable traits found in domestic animals are the result of relatively recent human-mediated selection, uncertainty remains as to whether the modern ubiquity of long-standing variable traits such as coat color results from selection or drift, and whether the underlying alleles were present in the wild ancestor or appeared after domestication began. Here, through an investigation of sequence diversity at the porcine melanocortin receptor 1 (MC1R) locus, we provide evidence that wild and domestic pig (Sus scrofa) haplotypes from China and Europe are the result of strikingly different selection pressures, and that coat color variation is the result of intentional selection for alleles that appeared after the advent of domestication. Asian and European wild boar (evolutionarily distinct subspecies) differed only by synonymous substitutions, demonstrating that camouflage coat color is maintained by purifying selection. In domestic pigs, however, each of nine unique mutations altered the amino acid sequence thus generating coat color diversity. Most domestic MC1R alleles differed by more than one mutation from the wild-type, implying a long history of strong positive selection for coat color variants, during which time humans have cherry-picked rare mutations that would be quickly eliminated in wild contexts. This pattern demonstrates that coat color phenotypes result from direct human selection and not via a simple relaxation of natural selective pressures.

J.Neuroscience：母亲经验能遗传给孩子

美国研究人员日前在《神经学杂志》（Journal of Neuroscience）上发表报告说，母亲能毫不费力地把她们的经验遗传给孩子。这项研究显示，幼鼠能够继承它们母亲怀孕之前获得的有益知识。
报道说，研究发现，在一个有玩具和其他刺激性物品丰富的环境里成长的幼鼠，在长大后能把学到的知识传给它们的幼崽。研究人员还发现，如果给刚出生的幼崽更换父母，只要幼崽的生母（而不是养父母）在有玩具的环境里长大，它们的幼崽仍然可以学习得更好。
波士顿塔夫茨大学药学院的生物化学教授拉里·法伊格说：“你能在一定程度上继承你父母某些方面的经验。”
法伊格还说：“这是母亲传给后代的一个保护性机制。这些未来的鼠妈妈几个月来一直在成长。它们的大脑也在成长，因此当它们长到可以怀孕时，这种效果仍然存在。”（ 生物谷 Bioon.com）
生物谷推荐原始出处：
Transgenerational Rescue of a Genetic Defect in Long-Term Potentiation and Memory Formation by Juvenile Enrichment
Junko A. Arai,1 * Shaomin Li,1 * Dean M. Hartley,2 and Larry A. Feig1
1Sackler School of Biomedical Sciences and Departments of Biochemistry and Neuroscience, Tufts University School of Medicine, Boston, Massachusetts 02111, and 2Department of Neurological Sciences, Rush University Medical Center, Chicago, Illinois 60612
The idea that qualities acquired from experience can be transmitted to future offspring has long been considered incompatible with current understanding of genetics. However, the recent documentation of non-Mendelian transgenerational inheritance makes such a "Lamarckian"-like phenomenon more plausible. Here, we demonstrate that exposure of 15-d-old mice to 2 weeks of an enriched environment (EE), that includes exposure to novel objects, elevated social interactions and voluntary exercise, enhances long-term potentiation (LTP) not only in these enriched mice but also in their future offspring through early adolescence, even if the offspring never experience EE. In both generations, LTP induction is augmented by a newly appearing cAMP/p38 MAP kinase-dependent signaling cascade. Strikingly, defective LTP and contextual fear conditioning memory normally associated with ras-grf knock-out mice are both masked in the offspring of enriched mutant parents. The transgenerational transmission of this effect occurs from the enriched mother to her offspring during embryogenesis. If a similar phenomenon occurs in humans, the effectiveness of one's memory during adolescence, particularly in those with defective cell signaling mechanisms that control memory, can be influenced by environmental stimulation experienced by one's mother during her youth.