Identification of a mutation in the CHAT gene of Old Danish Pointing Dogs affected with congenital myasthenic syndrome

The presence of a recessive inherited muscle disease in Old Danish Pointing Dogs has been well known for years. Comparisons of this disease with myasthenic diseases of other dog breeds and humans have pointed toward a defect in the synthesis of the neurotransmitter acetylcholine possibly due to decreased activity of the enzyme choline acetyltransferase. We sequenced exons 5-18 of the gene encoding choline acetyltransferase (CHAT) in 2 affected and 2 unaffected dogs and identified a G to A missense mutation in exon 6. The mutation causes a valine to methionine substitution and segregates in agreement with the inheritance of the disease. The mutation was not detected in 50 dogs representing 25 other dog breeds. A DNA test has been developed and is now available to the breeders of Old Danish Pointing Dogs.     

The sex-peptide gene (Acp70A) is duplicated in Drosophila subobscura

A 3.1-kb region of Drosophila subobscura homologous to the Acp70A region of D. melanogaster, which contains the sex-peptide gene, was cloned and sequenced. This region contains an approximately 600-bp duplication that includes the sex-peptide and its 5′ and 3′ flanking regions. The preproteins are 54 and 56 amino acids long, respectively (as compared to 55 amino acids in D. melanogaster), and each includes a 19-amino-acid-long signal peptide. The C-terminal part of the mature peptide is highly conserved between D. melanogaster and the two copies of D. subobscura. In this species, both copies of the gene are transcribed and, like in D. melanogaster, only expressed in males. The duplicated region includes 300 bp upstream of the gene that would therefore seem sufficient for their expression in males. This region presents at its 5′ end a stretch 93-bp that has a high similarity with the corresponding region of D. melanogaster and could be part of a still unidentified regulatory element of these genes.     

Mapping and expression studies of the mir17-92 cluster on pig Chromosome 11

We have identified the first porcine microRNA (miRNA) cluster (the mir17-92 cluster) and localized it to the q-arm of pig Chromosome 11. The miRNA cluster was found by sequence similarity search with human miRNA sequences against the pig genomic data generated within the Sino-Danish pig genome project. The resulting data contained three complete and two incomplete miRNA precursors of seven miRNAs from the human mir17-92 cluster. Because there is a 100% sequence identity between the four pig miRNAs and the corresponding human miRNAs, the sequences of three unavailable pig miRNAs were derived from the human data. The expression profiles of seven studied miRNAs were analyzed by hybridization to Northern blots containing five porcine tissues: cerebellum, cortex, hippocampus, kidney, and liver. In order to determine the localization of the mir17-92 cluster in the pig genome, we mapped it by PCR in the porcine somatic cell hybrid (SCH) panel and in the INRA-University of Minnesota (INRA-UMN) porcine radiation hybrid (IMpRH) panel. The PCR results enabled us to localize this cluster to the q-arm of pig Chromosome 11 and map it in relation to two microsatellites. Our study presents the first expression analyses of miRNAs in pig and adds information for further functional studies in this species.     

FISH mapping and sequence analysis of 87 porcine BAC clones

Ninety-one bacterial artificial chromosomes (BAC) clones, selected effectively at random from our library, were used as probes for fluorescence in situ hybridization. Of these, 87 clones gave a specific signal in one, two or three different pair(s) of swine metaphase chromosomes. The ends of 35 BAC clones were sequenced in order to obtain information for comparative mapping. Fifteen of them gave useful comparative mapping information.     

Investigation of tissue-specific human orthologous alternative splice events in pig

Alternative splicing of pre-mRNA can contribute to differences between tissues or cells either by regulating gene expression or creating proteins with various functions encoded by one gene. The number of investigated alternative splice events in pig has so far been limited. In this study we have investigated alternative splice events detected in humans, in orthologous pig genes. A total of 17 genes with predicted exon skipping events were selected for further studies. The splice events for the selected genes were experimentally verified using real-time quantitative PCR analysis (qPCR) with splice-specific primers in 19 different tissues. The same splice variants as reported in humans were detected in 15 orthologous pig genes, however, the expression pattern predicted in the in silico analyses was only experimentally verified in a few cases. The results support the findings that splice events resulting in preservation of open reading frame are indicative of a functional significance of the splice variants of the gene.     

Income distribution trends and future food demand

This paper surveys the theoretical literature on the relationship between income distribution and food demand, and identifies main gaps of current food modelling techniques that affect the accuracy of food demand projections. At the heart of the relationship between income distribution and food demand is Engel''s law. Engel''s law establishes that as income increases, households'' demand for food increases less than proportionally. A consequence of this law is that the particular shape of the distribution of income across individuals and countries affects the rate of growth of food demand. Our review of the literature suggests that existing models of food demand fail to incorporate the required Engel flexibility when (i) aggregating different food budget shares among households; and (ii) changing budget shares as income grows. We perform simple simulations to predict growth in food demand under alternative income distribution scenarios taking into account nonlinearity of food demand. Results suggest that (i) distributional effects are to be expected from changes in between-countries inequality, rather than within-country inequality; and (ii) simulations of an optimistic and a pessimistic scenario of income inequality suggest that world food demand in 2050 would be 2.7 per cent higher and 5.4 per cent lower than distributional-neutral growth, respectively.