A sequence-based variation map of 8.27 million SNPs in inbred mouse strains

A dense map of genetic variation in the laboratory mouse genome will provide insights into the evolutionary history of the species and lead to an improved understanding of the relationship between inter-strain genotypic and phenotypic differences. Here we resequence the genomes of four wild-derived and eleven classical strains. We identify 8.27 million high-quality single nucleotide polymorphisms (SNPs) densely distributed across the genome, and determine the locations of the high (divergent subspecies ancestry) and low (common subspecies ancestry) SNP-rate intervals for every pairwise combination of classical strains. Using these data, we generate a genome-wide haplotype map containing 40,898 segments, each with an average of three distinct ancestral haplotypes. For the haplotypes in the classical strains that are unequivocally assigned ancestry, the genetic contributions of the Mus musculus subspecies--M. m. domesticus, M. m. musculus, M. m. castaneus and the hybrid M. m. molossinus--are 68%, 6%, 3% and 10%, respectively; the remaining 13% of haplotypes are of unknown ancestral origin. The considerable regional redundancy of the SNP data will facilitate imputation of the majority of these genotypes in less-densely typed classical inbred strains to provide a complete view of variation in additional strains.     

Familiarity,application, and performance of sales forecasting techniques

This article presents the results of a survey to determine the degree of familiarity and usage, accuracy obtained, and evaluation of different forecasting techniques. It was found that regression analysis, subjective techniques, exponential smoothing, and moving average were well known and used for specific situations. Accuracy was relatively high for aggregate short range forecasts, but decreased for longer range and product level forecasts.     

Heterogeneity of macrophage cytophilic antibodies in immunized mice

Résumé Des souris immunisés avec des globules rouges de mouton dans l'adjuvant de Freund produisent deux types de facteurs cytophiles pour macrophages. L'un s'attache aux macrophages trypsinisées et se trouve parmi les immunoglobulines. L'autre ne s'attache pas aux macrophages trypsinisées et se rencontre dans une fraction de sérum contenant de l'albumine et de la globuline-₁.

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Supported by grants from the Australian Research Grants Committee, the National Health and Medical Research Council of Australia and the Postgraduate Medical Foundation, University of Sydney.     

DNA restriction fragments associated with alpha 1-antitrypsin indicate a single origin for deficiency allele PI Z

The alpha 1-protease inhibitor, or alpha-antitrypsin (AAT), a major plasma inhibitor of leukocyte elastase and bacterial proteases, is encoded at the PI locus on chromosome 14 (14q24.3-q32.1). A deficiency of AAT in individuals homozygous for the PI Z allele occurs in about 1 in 2,000-8,000 caucasians and is associated with an increased risk of early adult onset emphysema and liver disease in childhood. We have now used DNA polymorphisms associated with the AAT gene to investigate the origin of the PI Z allele. Using two genomic probes extending into the 5' and 3' flanking regions, respectively, we have identified eight polymorphic restriction sites. Extensive linkage disequilibrium occurs throughout the probed region with the PI Z allele, but not with normal PI M alleles. The Z allele occurs mainly with one haplotype, indicating a single, relatively recent, origin in caucasians.     

Incubation period of AIDS in patients infected via blood transfusion

Temporal trends in the prevalence of HIV (human immunodeficiency virus) infection are uncertain because of the reluctance of most governments to embark on large-scale programmes of serological surveillance. In the absence of such data, attempts have been made to relate the number of reported cases of AIDS (acquired immune deficiency syndrome) in a defined population to the proportion of that population infected with the virus as a specified time point. One crucial determinant of this relationship is the probability distribution of the incubation period of the disease, with the period defined as the time interval from infection to diagnosis. Recent statistical analysis suggests a mean incubation period of 4.5 years with wide confidence limits, whereas a more heuristic study reports a mean of 15 years. Here we report on a new analysis which reveals age-related differences in the mean (and median) incubation period: 1.97 (1.90) years for children (0-4 yrs old at infection), 8.23 (7.97) years for adults (5-59 yrs old), 5.50 (5.44) years for elderly patients (60 yrs and older).     

Increasing risk of Amazonian drought due to decreasing aerosol pollution

The Amazon rainforest plays a crucial role in the climate system, helping to drive atmospheric circulations in the tropics by absorbing energy and recycling about half of the rainfall that falls on it. This region (Amazonia) is also estimated to contain about one-tenth of the total carbon stored in land ecosystems, and to account for one-tenth of global, net primary productivity. The resilience of the forest to the combined pressures of deforestation and global warming is therefore of great concern, especially as some general circulation models (GCMs) predict a severe drying of Amazonia in the twenty-first century. Here we analyse these climate projections with reference to the 2005 drought in western Amazonia, which was associated with unusually warm North Atlantic sea surface temperatures (SSTs). We show that reduction of dry-season (July-October) rainfall in western Amazonia correlates well with an index of the north-south SST gradient across the equatorial Atlantic (the 'Atlantic N-S gradient'). Our climate model is unusual among current GCMs in that it is able to reproduce this relationship and also the observed twentieth-century multidecadal variability in the Atlantic N-S gradient, provided that the effects of aerosols are included in the model. Simulations for the twenty-first century using the same model show a strong tendency for the SST conditions associated with the 2005 drought to become much more common, owing to continuing reductions in reflective aerosol pollution in the Northern Hemisphere.