Anatomy of a media event: how arguments clashed in the 2001 human cloning debate

This paper studies the distinctive role that staged media events play in the public understanding of genetics: they can focus the attention of the media, scientists and the public on the risks and benefits of genetic advances, in our case, cloning; they can accelerate policy changes by exposing scientific, legal and ethical uncertainties; the use of images, metaphors, cliches, and cultural narratives by scientists and the media engaged in this event can reinforce stereotypical representations of cloning, but can also expose fundamental clashes in arguments about cloning. The media event staged by two fertility experts in 2001 is here analysed as a case study.     

Transmission patterns of eukaryotic transposable elements: arguments for and against horizontal transfer

Recent studies have demonstrated that several classes of transposable elements are widely distributed within eukaryotes. Horizontal transmission of these transposable elements has often been invoked In order to explain the observed variation and relationships within and between species. These same patterns of variation and relationships, however, may originate from processes that do not involve the lateral transfer of genetic material across species.     

Cytokinins and tRNAs: arguments against a hypothesis of cytokinin action

Arguments against the hypothesis of cytokinin action via competitive binding of cytokinin and cytokinin-containing tRNA to specific receptor proteins [Romanov (1990) Plant, Cell and Environment 13, 751–754] are presented. The hypothesis states that cereal genes containing a large number (4–8%) of the Leu codons TTG and TTA should be regulated by cytokinin at the translational level. In this paper, it is shown that the only genes that fulfil these hypothetical requirements are the ones encoding the heavy chain of zein. It is further shown that this is a consequence of the high Leu content of the encoded proteins and the lack of GC bias of the genes.     

Thermodynamic arguments for temperature-induced cryptic conformational change of human plasma cholinesterase

The temperature and pressure dependence of the kinetics of the hydrolysis of o-nitrophenylbutyrate by human plasma tetrameric form cholinesterase (EC 3.1.1.8) was studied. The study was carried out on the one hand at atmospheric pressure by spectrophotometry at various temperatures ranging from 0 to 40 degrees C and, on the other hand by high-pressure stopped-flow spectrophotometry at 3.5, 25 and 35 degrees C in the pressure range 10(-3) to 2 kbar. The Arrhenius plot showed a break at 21 +/- 1 degrees C. Kinetic parameters, activation parameters and volume changes are reported. Discontinuities in the thermodynamic quantities obtained from temperature and pressure (up to 0.8 kbar) dependence of hydrolysis rates are discussed; they have been interpreted as the result of a temperature-induced cryptic conformational change of the enzyme at around 20 degrees C. Beyond 1 kbar the kinetics exhibited several complexities: curvature of the progress curves and high positive or negative activation volume changes depending on temperature and substrate concentration. These complex interacting effects between temperature, pressure and substrate concentration are discussed.     

Application of reproductive biotechnology in animals: implications and potentials. Applications of reproductive cloning

The development of new methods of nuclear transfer in mammals is creating many new opportunities in research, medicine and agriculture. The method of cloning is repeatable and has been established in many laboratories worldwide. However, the present procedure is inefficient with fewer than 4% of embryos becoming viable offspring. A considerable improvement in efficiency is required before wide scale use for livestock improvement. The opportunity to introduce precise genetic changes to livestock is available for the first time through the use of gene targeting procedures in cultured cells that are used as nuclear donors. This has potential application in the production of organs for transplantation to humans, studies of human genetic disease and basic research in to the control of gene expression and function.     

Molecular cloning and characterization of cDNA for human myeloperoxidase

Partial amino acid sequence of human myeloperoxidase was determined, and a 41-base oligonucleotide containing deoxyinosines at four positions was chemically synthesized. By using the oligonucleotide as a probe, cDNA clones for human myeloperoxidase were isolated from a cDNA library constructed with mRNA from human promyelocytic leukemia HL-60 cells. One of the clones containing a 2.6-kilobase insert was subjected to nucleotide sequence analysis. The sequence was found to contain an open reading frame, 2,235 nucleotides coding for a protein of 745 amino acids with a calculated Mr of 83,868. The heavy chain of myeloperoxidase, consisting of 467 amino acids, was located on the COOH terminus half of the protein. The RNA specified by the cDNA was prepared using SP6 RNA polymerase and translated in rabbit reticulocyte lysates, and the product was identified as human myeloperoxidase by immunoprecipitation with rabbit anti-human myeloperoxidase antibody. By Northern hybridization analysis of RNA from leukemic cells, it was shown that myeloperoxidase mRNA is abundantly expressed in human promyelocytic HL-60 and mouse myeloid leukemia NFS-60 cells. Furthermore, the results of Southern hybridization analysis of human genomic DNA suggest that there are one or two genes for myeloperoxidase in the human haploid genome.     

On cloning human beings

The purpose of this paper is to show that arguments for and against cloning fail to make their case because of one or both of the following reasons: 1) they take for granted customary beliefs and assumptions that are far from being unquestionable; 2) they tend to ignore the context in which human cloning is developed. I will analyze some of the assumptions underlying the main arguments that have been offered for and against cloning. Once these assumptions are critically analyzed, arguments both rejecting and supporting human cloning seem to lose weight. I will first briefly present the main arguments that have been proposed against cloning and I will argue that they fail to establish their case. In the next section I will evaluate some of the positive arguments that have been offered supporting such technology. This analysis will show that the case for cloning also fails. Finally, I will maintain that because critics and especially supporters of this technology neglect the context in which human cloning is developed and might be implemented, their arguments are far from compelling.     

Methodological problems in evolutionary biology II. Appraisal of arguments against adaptationism

Methodological analysis shows that the concepts of fitness and adaptation are more complex than the literature suggests. Various arguments against ‘adaptationism’ are inadequate since they are couched in terms of unduly simplistic notions.     

Unexpected findings in identifiable stored blood samples after analysis without consent: moral arguments for and against disclosure

Obtaining informed consent for using blood samples in research is mandatory. However, sometimes no consent is obtained for analysis of identifiable blood samples in a second study. As a result, a moral dilemma raises in case a possibly pathogenic mutation is found. Should the involved person be informed that such a mutation has been detected? We present a case in which this problem occurred and discuss arguments for and against information disclosure.     

The arguments for pre-existing early and late endosomes

The past decade has seen the elucidation of many of the events and processes responsible for receptor-mediated endocytosis. However, a fundamental question about the endocytic pathway remains unresolved: do early endosomes mature into late endosomes, or are these two distinct and pre-existing cellular organelles? General opinion tends to favour the former possibility, to the point where one poster session at the recent American Society for Cell Biology meeting was entitled 'Maturation of Endosomes'. This article draws together new data arguing in favour of pre-existing early and late endosomes, between which transport occurs by vesicle budding and fusion.     

Molecular cloning of cDNA for human prostatic acid phosphatase

A human liver cDNA library in λgt11 was screened with polyclonal antiserum to human acid phosphatase isoenzyme 2a/4. About eleven positive clones have been obtained. Two clones, λ Hap21 and λ Hap22 were further characterized: clone λHap21 contained a 0.8-kb cDNA insert and clone λHap22 a 1.8–2.0-kb insert. XbaI digestion of λHap22 generated two fragments of 1.0 and 0.9 kb. BglII digestion resulted in a 1.2-kb fragment and several smaller fragments of undetermined size. Clone 1 Hap22 contained all the genes carried by λ gt11(lac 5cI857nin 5Sam 100) and the 2-kb insert. An Escherichia coli(λHap22) lysogen was generated, and its acid phosphatase activity was approximately ten-fold higher than that in the control nonlysogenic lysate. Western-blot analysis of total proteins present in this E. coli(λHap22) lysate revealed that the non-induced λHap22 prophage directed the synthesis of an approx. 175-kDa protein. This protein was recognized by antibody to the human acid phosphatase isoenzyme 2a/4 and anti-β-galactosidase and was produced only upon induction with IPTG. These results indicated that AHap22 carried a major portion of the gene coding for the human acid phosphatase isoenzyme 2a and/or 4 and this protein fragment of acid phosphatase was sufficient to manifest enzymatic activity.     

Molecular cloning of a cDNA for human delta-aminolevulinate dehydratase

A cDNA encoding human delta-aminolevulinic acid dehydratase (ALA-D; EC 4.2.1.24), the second enzyme in the heme biosynthetic pathway, was isolated from a human liver cDNA expression library. Of the original 17 clones selected with anti-ALA-D antibody, only four expressed anti-ALA-D epitopes as assessed by rescreening with antibody preabsorbed with purified antigen. Subsequent screening of the antibody-positive clones with mixed oligodeoxynucleotide (oligo) probes, synthesized to correspond to human N-terminal and bovine active-site peptide sequences, identified three clones which hybridized only with the oligo probes for the bovine amino acid (aa) sequences. Restriction endonucleases analysis revealed that these three clones contained the same 800-bp cDNA insert. This insert was recloned into bacteriophage M13mp18 and mp19 and sequenced by primer extension. The aa sequence predicted from the partial nucleotide sequence was found to be essentially colinear with the sequences of four bovine ALA-D peptides, totaling 35 non-overlapping aa residues.