Modifying the mammalian genome by gene targeting

Over the past year, gene targeting in mammalian cells has become a facile technology. By using a variety of selection and screening protocols, it has become possible to direct modifications at the nucleotide level to specific genes, to target marker genes so that they become expressed under the control of endogenous promoters and to delete large regions of the genome.     

Vaccines for the twenty-first century society

Vaccines have been one of the major revolutions in the history of mankind and, during the twentieth century, they eliminated most of the childhood diseases that used to cause millions of deaths. In the twenty-first century, vaccines will also play a major part in safeguarding people's health. Supported by the innovations derived from new technologies, vaccines will address the new needs of a twenty-first century society characterized by increased life expectancy, emerging infections and poverty in low-income countries.     

Crop photosynthesis for the twenty-first century

Photosynthesis Research -     

Culture collections in the twenty-first century

Culture collections conserve the living tools for biotechnology. Without them there would be no reference organisms, and no stocks of crucial or rare microorganisms that are so valuable for biotechnology and biomedical research. The expertise that drives these collections is under threat, but the collections themselves may survive by pooling their knowledge.     

Intracellular targeting and functional analysis of single-chain Fv fragments in mammalian cells

In the past decade, intracellular antibodies have proven to be a useful tool in obtaining the phenotypic knock-out of selected gene function in different animal and plant systems. This strategy is based on the ectopic expression of recombinant forms of antibodies targeted towards different intracellular compartments, exploiting specific targeting signals to confer the new intracellular location. The functional basis of this technology is closely linked to the ability of intracellular antibodies to interact with their target antigens in vivo. This interaction allows either a direct neutralising effect or the dislodgement of the target protein from its normal intracellular location and, by this mechanism, the inactivation of its function. By using this approach, the function of several antigens has been inhibited in the cytoplasm, the nucleus, and the secretory compartments. In this article, we shall describe all the steps required for expressing single-chain Fv fragments in different subcellular compartments of mammalian cells and their subsequent use in knock-out experiments, starting from a cloned single-chain Fv fragment. This will include the analysis of the solubility properties of the new scFv fragment in transfected mammalian cells, the intracellular distribution of the antigen-antibody complex, and the resulting phenotype.     

Plant drugs in the twenty-first century

Lack of effective cooperation among researchers in the applicable biological, physical, and clinical sciences has accounted, in large measure, for the lack of successful development in the United States of any significant number of new plant drugs during the latter part of the 20th century. Unrealistic federal regulations that tend to render unprofitable such research have also played an important role in hindering the development of new plant drugs. It is likely that both of these factors will change in the future as health-conscious consumers demand more accurate information and wider availability of natural drug products. Several anticipated developments will greatly facilitate research and production in this previously difficult area. These include the development of new, simplified bioassay procedures; improved, easily applied analytical methods; and innovative plant-cell-culture methodologies, possibly involving genetic manipulation. The kinds of drugs that need to be developed using such techniques are discussed. It is concluded that significant new plant drugs and new methods of producing them will be developed to serve mankind during the 21st century.     

Noah and the spaceship: evolution for twenty-first century christians

Evolution has increasingly become a topic of conflict between scientists and Christians, but Alexandre Meinesz’s recent book How Life Began aims to provide a reconciliation between the two. Here I review his somewhat unorthodox perspective on major transitions, alien origins and the meaning of life, with a critical focus on his account of the generation of multicellularity.     

LCA in Japan in the twenty-first century

The International Journal of Life Cycle Assessment -       

Evidence for turnover of functional noncoding DNA in mammalian genome evolution

The vast majority of the mammalian genome does not code for proteins, and a fundamental question in genomics is: What proportion of the noncoding mammalian genome is functional? Most attempts to address this issue use sequence comparisons between highly diverged mammals such as human and mouse to identify conservation due to negative selection. But such comparisons will underestimate the true proportion of functional noncoding DNA if there is turnover, if patterns of negative selection change over time. Here we test whether the inferred level of negative selection differs between different pairwise species comparisons. Using a multiple alignment of more than a megabase of contiguous sequence from eight mammalian species, we find a strong negative relationship between inferred levels of negative selection and pairwise divergence using 21 pairwise comparisons. This result suggests that there is a high rate of turnover of functional noncoding elements in the mammalian genome, so measures of functional constraint based on human-mouse comparisons may seriously underestimate the true value.     

Gene targeting,genome editing: from Dolly to editors

One of the most powerful strategies to investigate biology we have as scientists, is the ability to transfer genetic material in a controlled and deliberate manner between organisms. When applied to livestock, applications worthy of commercial venture can be devised. Although initial methods used to generate transgenic livestock resulted in random transgene insertion, the development of SCNT technology enabled homologous recombination gene targeting strategies to be used in livestock. Much has been accomplished using this approach. However, now we have the ability to change a specific base in the genome without leaving any other DNA mark, with no need for a transgene. With the advent of the genome editors this is now possible and like other significant technological leaps, the result is an even greater diversity of possible applications. Indeed, in merely 5 years, these ‘molecular scissors’ have enabled the production of more than 300 differently edited pigs, cattle, sheep and goats. The advent of genome editors has brought genetic engineering of livestock to a position where industry, the public and politicians are all eager to see real use of genetically engineered livestock to address societal needs. Since the first transgenic livestock reported just over three decades ago the field of livestock biotechnology has come a long way—but the most exciting period is just starting.     

Biological systems modeling and analysis: a biomolecular technique of the twenty-first century.

It is proposed that computational systems biology should be considered a biomolecular technique of the twenty-first century, because it complements experimental biology and bioinformatics in unique ways that will eventually lead to insights and a depth of understanding not achievable without systems approaches. This article begins with a summary of traditional and novel modeling techniques. In the second part, it proposes concept map modeling as a useful link between experimental biology and biological systems modeling and analysis. Concept map modeling requires the collaboration between biologist and modeler. The biologist designs a regulated connectivity diagram of processes comprising a biological system and also provides semi-quantitative information on stimuli and measured or expected responses of the system. The modeler converts this information through methods of forward and inverse modeling into a mathematical construct that can be used for simulations and to generate and test new hypotheses. The biologist and the modeler collaboratively interpret the results and devise improved concept maps. The third part of the article describes software, BST-Box, supporting the various modeling activities.     

Gene function in the mammalian genome,courtesy of the mouse

A report on the 16th International Mouse Genome Conference, San Antonio, USA, 17-20 November, 2002.     

Gene mapping of the mammalian genome: The CEPH and genethon initiative

Over the past four years, the CEPH (Jean Dausset Foundation) has expanded its linkage mapping effort to include physical mapping and, in 1990, co-founded the Genethon to ensure that a combined physical and genetic map of the entire human genome would be achieved. The Genethon has applied methods developed at CEPH on an industrial scale to accomplish the colossal task of constructing an integrated map. It is the role of such an integrated map to accelerate the search for the genes responsible for inherited diseases, and the results of the past 12 months encourage our optimism that this goal will be realized rapidly. These discoveries are providing not only an approach to the diagnosis of genetically based disease but also some of the first breakthroughs in the area of gene therapy.     

Marker-assisted selection: an approach for precision plant breeding in the twenty-first century

DNA markers have enormous potential to improve the efficiency and precision of conventional plant breeding via marker-assisted selection (MAS). The large number of quantitative trait loci (QTLs) mapping studies for diverse crops species have provided an abundance of DNA marker-trait associations. In this review, we present an overview of the advantages of MAS and its most widely used applications in plant breeding, providing examples from cereal crops. We also consider reasons why MAS has had only a small impact on plant breeding so far and suggest ways in which the potential of MAS can be realized. Finally, we discuss reasons why the greater adoption of MAS in the future is inevitable, although the extent of its use will depend on available resources, especially for orphan crops, and may be delayed in less-developed countries. Achieving a substantial impact on crop improvement by MAS represents the great challenge for agricultural scientists in the next few decades.