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The article announces the standards for all research papers on cloning by "Nature." The periodical is asking the authors to provide nuclear and mitochondrial DNA fingerprints for all cloning papers submitted for publication. Nuclear DNA fingerprints of the lines should be presented for comparison with existing lines, in the case of papers disclosing new embryonic stem cell lines.

A letter to the editor in response to the article "Standards for Papers on Cloning" published in the 2006 issue of "Nature" is presented.

A letter to the editor in response to the article "Standards for Papers on Cloning" published in the 2006 issue is presented.

The article cites an inquiry from the blog of the Web site, Nature Reports Stem Cells. It is asked how the journal "Nature" could improve its peer-review process for papers about cloning. This question is aimed at preventing the publication of fallacious data. One question points to the adequacy of the review procedure for the refereeing of cloning papers.

A letter to the editor is presented in response to the article "Standards for papers on cloning" in the 2006 issue.

A letter to the editor is presented in response to the article "Standard for Papers on Cloning," in the 2006 issue.

Provides background and analysis of a paper which reports a procedure to obtain viable lambs from cell lines that have been established from more mature embryos. The use of a cell line from the udder of a six-year old ewe; History of attempts to clone mammals; The implications for genome development; The paper in the February 27, 1997 `Nature.'

Discusses the technical obstacles faced by companies seeking to develop cloning technologies in the United States. Woes of the biotechnology sector; Announcement by PPL Therapeutics that it has cloned genetically modified pigs; Xenotransplantation.

Opinion. Examines the implications of Richard Seed's intention to clone humans in Chicago, Illinois. Seed's naivety and hubris; Possible benefits of Seed's behavior; Seed's excesses polarizing the debate; Distinctions in cloning debate; Declarations at national and international levels; Scientific possibilities and social pitfalls of cloning; Upcoming paper from Britain's Human Genetics Advisory Commission.

The article reports that Gerald Schatten which was recently exposed for faking the results of cloning experiments was cleared of misconduct by University of Pittsburgh in Philadelphia, Pennsylvania. An investigation was conducted by the university after claims in a paper that he had co-authored the cloning research which turned out to be false.

The article focuses on the issues concerning the animal cloning experiments of South Korean scientist Woo Suk Hwang. Other scientists claimed that the research lacks evidence. Hwang however admitted that there were errors in the 2005 stem-cell paper, but denied fraud. He claimed that 11 patient-specific stem-cell lines were created as reported but six were never frozen as opposed to the claims of other scientists. Furthermore, the science community have expressed their concerns over the implication of the controversy to cell research.

Human cancers, including breast cancers, comprise clones differing in mutation content. Clones evolve dynamically in space and time following principles of Darwinian evolution, underpinning important emergent features such as drug resistance and metastasis. Human breast cancer xenoengraftment is used as a means of capturing and studying tumour biology, and breast tumour xenografts are generally assumed to be reasonable models of the originating tumours. However, the consequences and reproducibility of engraftment and propagation on the genomic clonal architecture of tumours have not been systematically examined at single-cell resolution. Here we show, using deep-genome and single-cell sequencing methods, the clonal dynamics of initial engraftment and subsequent serial propagation of primary and metastatic human breast cancers in immunodeficient mice. In all 15 cases examined, clonal selection on engraftment was observed in both primary and metastatic breast tumours, varying in degree from extreme selective engraftment of minor (<5% of starting population) clones to moderate, polyclonal engraftment. Furthermore, ongoing clonal dynamics during serial passaging is a feature of tumours experiencing modest initial selection. Through single-cell sequencing, we show that major mutation clusters estimated from tumour population sequencing relate predictably to the most abundant clonal genotypes, even in clonally complex and rapidly evolving cases. Finally, we show that similar clonal expansion patterns can emerge in independent grafts of the same starting tumour population, indicating that genomic aberrations can be reproducible determinants of evolutionary trajectories. Our results show that measurement of genomically defined clonal population dynamics will be highly informative for functional studies using patient-derived breast cancer xenoengraftment. [ABSTRACT FROM AUTHOR]

The article reports on Korean researcher Woo Suk Hwang's application for a new license to work on human embryonic stem cells to replace his revoked one. Hwang's license was revoked after it was found out that his 2006 work on human embryonic stem cells was fabricated. He is still on trial after being charged with fraud, embezzlement and violation of Korean bioethics law. His application is expected to be decided by the Korean science ministry on April 2008. Aside from his license application, Hwang's name also appeared on at least three papers, that discuss improvements in pig cloning from new methods of cultivating porcine eggs, which he worked on after he was fired at the Seoul National University in South Korea.

Recent studies using the isolation of a subpopulation of tumour cells followed by their transplantation into immunodeficient mice provide evidence that certain tumours, including squamous skin tumours, contain cells with high clonogenic potential that have been referred to as cancer stem cells (CSCs). Until now, CSC properties have only been investigated by transplantation assays, and their existence in unperturbed tumour growth is unproven. Here we make use of clonal analysis of squamous skin tumours using genetic lineage tracing to unravel the mode of tumour growth in vivo in its native environment. To this end, we used a genetic labelling strategy that allows individual tumour cells to be marked and traced over time at different stages of tumour progression. Surprisingly, we found that the majority of labelled tumour cells in benign papilloma have only limited proliferative potential, whereas a fraction has the capacity to persist long term, giving rise to progeny that occupy a significant part of the tumour. As well as confirming the presence of two distinct proliferative cell compartments within the papilloma, mirroring the composition, hierarchy and fate behaviour of normal tissue, quantitative analysis of clonal fate data indicates that the more persistent population has stem-cell-like characteristics and cycles twice per day, whereas the second represents a slower cycling transient population that gives rise to terminally differentiated tumour cells. Such behaviour is shown to be consistent with double-labelling experiments and detailed clonal fate characteristics. By contrast, measurements of clone size and proliferative potential in invasive squamous cell carcinoma show a different pattern of behaviour, consistent with geometric expansion of a single CSC population with limited potential for terminal differentiation. This study presents the first experimental evidence for the existence of CSCs during unperturbed solid tumour growth. [ABSTRACT FROM AUTHOR]

A fundamental feature of the mammalian neocortex is its columnar organization. In the visual cortex, functional columns consisting of neurons with similar orientation preferences have been characterized extensively, but how these columns are constructed during development remains unclear. The radial unit hypothesis posits that the ontogenetic columns formed by clonally related neurons migrating along the same radial glial fibre during corticogenesis provide the basis for functional columns in adult neocortex. However, a direct correspondence between the ontogenetic and functional columns has not been demonstrated. Here we show that, despite the lack of a discernible orientation map in mouse visual cortex, sister neurons in the same radial clone exhibit similar orientation preferences. Using a retroviral vector encoding green fluorescent protein to label radial clones of excitatory neurons, and in vivo two-photon calcium imaging to measure neuronal response properties, we found that sister neurons preferred similar orientations whereas nearby non-sister neurons showed no such relationship. Interestingly, disruption of gap junction coupling by viral expression of a dominant-negative mutant of Cx26 (also known as Gjb2) or by daily administration of a gap junction blocker, carbenoxolone, during the first postnatal week greatly diminished the functional similarity between sister neurons, suggesting that the maturation of ontogenetic into functional columns requires intercellular communication through gap junctions. Together with the recent finding of preferential excitatory connections among sister neurons, our results support the radial unit hypothesis and unify the ontogenetic and functional columns in the visual cortex. [ABSTRACT FROM AUTHOR]

The article reports world news briefs in science. An official inquiry found that the Mars Global Surveyor spacecraft was lost due to a series of errors originating with a programming flaw. A research paper from Seoul National University in Korea that reported the first cloned wolf has been questioned as possibly fraudulent.

Presents a correction to the article "Cloning of Adiponectin Receptors That Mediate Antidiabetic Metabolic Effects," by Toshimasa Yamauchi and colleagues, published in the October 2004 issue of the periodical "Nature".

Presents insights into the ethical aspect of a therapeutic cloning experiment in South Korea. Concerns raised on the way the researchers managed to recruit so many women prepared to donate their eggs; Responsibility of the principal investigators to demonstrate that safeguards are applied; Role of local regulators to give ethical approval for the project.

Cooperation is central to many major transitions in evolution, including the emergence of eukaryotic cells, multicellularity and eusociality. Cooperation can be destroyed by the spread of cheater mutants that do not cooperate but gain the benefits of cooperation from others. However, cooperation can be preserved if cheaters are facultative, cheating others but cooperating among themselves. Several cheater mutants have been studied before, but no study has attempted a genome-scale investigation of the genetic opportunities for cheating. Here we describe such a screen in a social amoeba and show that cheating is multifaceted by revealing cheater mutations in well over 100 genes of diverse types. Many of these mutants cheat facultatively, producing more than their fair share of spores in chimaeras, but cooperating normally when clonal. These findings indicate that phenotypically stable cooperative systems may nevertheless harbour genetic conflicts. The opportunities for evolutionary moves and countermoves in such conflicts may select for the involvement of multiple pathways and numerous genes. [ABSTRACT FROM AUTHOR]

Copy number variation (CNV) of DNA sequences is functionally significant but has yet to be fully ascertained. We have constructed a first-generation CNV map of the human genome through the study of 270 individuals from four populations with ancestry in Europe, Africa or Asia (the HapMap collection). DNA from these individuals was screened for CNV using two complementary technologies: single-nucleotide polymorphism (SNP) genotyping arrays, and clone-based comparative genomic hybridization. A total of 1,447 copy number variable regions (CNVRs), which can encompass overlapping or adjacent gains or losses, covering 360 megabases (12% of the genome) were identified in these populations. These CNVRs contained hundreds of genes, disease loci, functional elements and segmental duplications. Notably, the CNVRs encompassed more nucleotide content per genome than SNPs, underscoring the importance of CNV in genetic diversity and evolution. The data obtained delineate linkage disequilibrium patterns for many CNVs, and reveal marked variation in copy number among populations. We also demonstrate the utility of this resource for genetic disease studies. [ABSTRACT FROM AUTHOR]

Cloning by nuclear transplantation has been successfully carried out in various mammals, including mice. Until now mice have not been cloned from post-mitotic cells such as neurons. Here, we have generated fertile mouse clones derived by transferring the nuclei of post-mitotic, olfactory sensory neurons into oocytes. These results indicate that the genome of a post-mitotic, terminally differentiated neuron can re-enter the cell cycle and be reprogrammed to a state of totipotency after nuclear transfer. Moreover, the pattern of odorant receptor gene expression and the organization of odorant receptor genes in cloned mice was indistinguishable from wild-type animals, indicating that irreversible changes to the DNA of olfactory neurons do not accompany receptor gene choice. [ABSTRACT FROM AUTHOR]

Presents a study from Japan's RIKEN Mouse Gene Encyclopaedia Project, which is working systematically to determine the full coding potential of the mouse genome. Description of the first RIKEN clone collection; Annotation and analysis of these cDNAs; Strategies; cDNAs which represent metabolic enzymes; Orthologues of human disease genes; Identification of mouse genes; Determination of protein domains and families; Protein motifs; Untranslated regions; Chromosomal mapping of cDNA clones.

Reports on the successful cloning of pigs. Discussion of the cloning process for animals such as sheep and goats which involves the transplant of diploid donor nuclei into enucleated MII oocytes; Results of the nuclear transfer process on pigs which was unsuccessful; Details of a successful pig cloning which involved a two-stage nuclear transfer procedure.

Opinion. Examines the debate about whether the sheep Dolly was cloned from fetal or adult cells. Controversy about the burden of proof in such experiments; Defining the threshold of proof; Probability that research will stand; Formal publication of research not being the last word; Desirability of public debate of scientific views.

Presents details on scientific equipment for July 8, 1999. Cloning disks from Bel-Art; Transgenic proteins from Genzyme/Invitrogen; Automated sequencing from Sigma; ChemScanRDI from Chemunex.

Reports the construction of a tiling path of around 650 clones covering more than ninety-nine percent of human chromosome 14. Clone overlap information which was derived by comparing fully sequenced clones with a database of clone end sequences; Selection of homogeneously distributed seed points using an auxiliary high-resolution radiation hybrid map; Long-range continuity and low redundancy of the tiling path, which indicates that the method compares favorably with alternative gene mapping techniques.

Reports the construction of maps for chromosomes 1, 6, 9, 10, 13, 20, and X, by building landmark maps, isolating bacterial clones and assembling contigs. Ability to establish the long-range organization of the maps early in the project using this approach; Simplification of contig extension, gap closure, and problem-solving with this method because of containment within local regions; Percentage of the euchromatic regions and chromosome-specific markers in the human gene map which these represent; Applications for assessing sequenced clones.

Presents science-related news items, as of December 18, 2003. Death Edward Teller, brainchild of the hydrogen bomb; Crash of the Galileo, a planetary probe, into Jupiter to prevent it from crashing into and polluting Europa, which many believe harbor extraterrestrial life; Death of Dolly, the cloned sheep.

Focuses on the lack of ethical grounds for banning safe reproductive cloning. Role of safe cloning in the satisfaction of reproductive or familial needs; Distinction between cloning by infertile persons to establish a family connection and cloning by fertile persons to choose the genotype of a child.