Armut im Kontext reicher Staaten: zur wissenschaftlichen Operationalisierung eines normativen Begriffs

Eine der Schwierigkeiten bei der wissenschaftlichen Beschäftigung mit dem Themenbereich "Armut" ist der normative Gehalt dieses Konzepts. Das hat unter anderem damit zu tun, dass der Begriff nicht nur in wissenschaftlichen Analysen, sondern auch in der Alltagssprache verwendet und dabei zum Teil deutlich unterschiedlich definiert wird. Vor dem Hintergrund dieser Problematik hat es etliche Versuche gegeben, die wissenschaftliche Definition von Armut stärker an das Alltagsverständnis der Bevölkerung anzugleichen. Dabei zeigt sich, dass theoretisch-konzeptuelle Arbeiten zur exakten Formulierung des sozialen Phänomens "Armut" im Verlauf des letzten Jahrhunderts weit gediehen sind. Die empirische Umsetzbarkeit dieser Überlegungen stößt allerdings nach wie vor auf Grenzen, wie anhand von jüngeren Beispielen der Armutsberichterstattung für den EU- und OECD-Raum gezeigt wird.One of the difficulties in the scientific analysis of poverty is the normative content of this concept. This is not least based on the fact that the notion "poverty" is not only used for scientific purposes, but also by the population at large - with partly profound differences with regard to its interpretation. Against the background of this difficulty, several efforts have been made to adopt the scientific definition of poverty to more closely capture its public meaning. The conceptual-theoretical work to operationalise poverty has gone a long way within the last century. However, there are still quite some difficulties in translating the "new" concepts (which also lead to the establishment of alternative terminologies, e.g. "poverty risk" or "social exclusion") into practice, as is shown regarding recent examples of poverty reports for the region of the European Union and the OECD

The Homeotic Gene <i>lin-39</i> and the Evolution of Nematode Epidermal Cell Fates

The fate of ventral epidermal cells differs among nematode species. Nonvulval cells fuse with the epidermis in Caenorhabditis elegans , whereas the homologous cells undergo apoptosis in Pristionchus pacificus . The homeotic gene lin-39 is involved in the regulation of these epidermal cell fates. In Caenorhabditis , lin-39 prevents cell fusion of potential vulval cells and specifies the vulva equivalence group. Pristionchus vulvaless mutants that displayed apoptosis of the vulval precursor cells were isolated, and point mutations in lin-39 were identified. Thus, the evolution of these epidermal cell fates is driven by different intrinsic properties of homologous cells. </jats:p

Limited microsynteny between the genomes of Pristionchus pacificus and Caenorhabditis elegans

Nematodes are an attractive group of organisms for studying the evolution of developmental processes. Pristionchus pacificus was established as a satellite organism for comparing vulva development and other processes to Caenorhabditis elegans. The generation of a genetic linkage map of P.pacificus has provided a first insight into the structure and organization of the genome of this species. Pristionchus pacificus and C.elegans are separated from one another by >100 000 000 years such that the structure of the genomes of these two nematodes might differ substantially. To evaluate the amount of synteny between the two genomes, we have obtained 126 kb of continuous genomic sequence of P.pacificus, flanking the developmental patterning gene pal-1. Of the 20 predicted open reading frames in this interval, 11 have C.elegans orthologs. Ten of these 11 orthologs are located on C.elegans chromosome III, indicating the existence of synteny. However, most of these genes are distributed over a 12 Mb interval of the C.elegans genome and only three pairs of genes show microsynteny. Thus, intrachromosomal rearrange ments occur frequently in nematodes, limiting the likelihood of identifying orthologous genes of P.pacificus and C.elegans based on positional information within the two genomes

Synapsis-Defective Mutants Reveal a Correlation Between Chromosome Conformation and the Mode of Double-Strand Break Repair During Caenorhabditis elegans Meiosis

SYP-3 is a new structural component of the synaptonemal complex (SC) required for the regulation of chromosome synapsis. Both chromosome morphogenesis and nuclear organization are altered throughout the germlines of syp-3 mutants. Here, our analysis of syp-3 mutants provides insights into the relationship between chromosome conformation and the repair of meiotic double-strand breaks (DSBs). Although crossover recombination is severely reduced in syp-3 mutants, the production of viable offspring accompanied by the disappearance of RAD-51 foci suggests that DSBs are being repaired in these synapsis-defective mutants. Our studies indicate that once interhomolog recombination is impaired, both intersister recombination and nonhomologous end-joining pathways may contribute to repair during germline meiosis. Moreover, our studies suggest that the conformation of chromosomes may influence the mode of DSB repair employed during meiosis

SYP-3 Restricts Synaptonemal Complex Assembly to Bridge Paired Chromosome Axes During Meiosis in Caenorhabditis elegans

Synaptonemal complex (SC) formation must be regulated to occur only between aligned pairs of homologous chromosomes, ultimately ensuring proper chromosome segregation in meiosis. Here we identify SYP-3, a coiled-coil protein that is required for assembly of the central region of the SC and for restricting its loading to occur only in an appropriate context, forming structures that bridge the axes of paired meiotic chromosomes in Caenorhabditis elegans. We find that inappropriate loading of central region proteins interferes with homolog pairing, likely by triggering a premature change in chromosome configuration during early prophase that terminates the search for homologs. As a result, syp-3 mutants lack chiasmata and exhibit increased chromosome missegregation. Altogether, our studies lead us to propose that SYP-3 regulates synapsis along chromosomes, contributing to meiotic progression in early prophase

A Gene Expression Map for <i>Caenorhabditis elegans</i>

We have assembled data from Caenorhabditis elegans DNA microarray experiments involving many growth conditions, developmental stages, and varieties of mutants. Co-regulated genes were grouped together and visualized in a three-dimensional expression map that displays correlations of gene expression profiles as distances in two dimensions and gene density in the third dimension. The gene expression map can be used as a gene discovery tool to identify genes that are co-regulated with known sets of genes (such as heat shock, growth control genes, germ line genes, and so forth) or to uncover previously unknown genetic functions (such as genomic instability in males and sperm caused by specific transposons). </jats:p