Abstract In situ hybridization, using a biotinylated cDNA probe for the epidermal growth factor receptor (EGFR) gene, indicates that the amplified EGFR genes in the colon tumor cell line, DiFi, are localized in many small double minute chromosomes (dmin) of varying size and visibility. Analysis of the electrophoretic mobility of γ‐irradiated DNA from DiFi by pulsed‐field gel electrophoresis and Southern blot hybridization using EGFR probe, indicates that the amplified EGFR in DiFi exists in extrachromosomal, covalently closed circular episomes, presumably equivalent to dmin. Two major and one minor species were observed which had estimated sizes of 650, 1,300, and 2,000 kb, respectively. The DiFi cell line appears to represent a unique case of extrachromosomal EGFR gene amplification in human cells.
Abstract Background Non-synonymous polymorphisms within the prion protein gene ( PRNP ) influence the susceptibility and incubation time for transmissible spongiform encephalopathies (TSE) in some species such as sheep and humans. In cattle, none of the known polymorphisms within the PRNP coding region has a major influence on susceptibility to bovine spongiform encephalopathy (BSE). Recently, however, we demonstrated an association between susceptibility to BSE and a 23 bp insertion/deletion (indel) polymorphism and a 12 bp indel polymorphism within the putative PRNP promoter region using 43 German BSE cases and 48 German control cattle. The objective of this study was to extend this work by including a larger number of BSE cases and control cattle of German and Swiss origin. Results Allele, genotype and haplotype frequencies of the two indel polymorphisms were determined in 449 BSE cattle and 431 unaffected cattle from Switzerland and Germany including all 43 German BSE and 16 German control animals from the original study. When breeds with similar allele and genotype distributions were compared, the 23 bp indel polymorphism again showed a significant association with susceptibility to BSE. However, some additional breed-specific allele and genotype distributions were identified, mainly related to the Brown breeds. Conclusion Our study corroborated earlier findings that polymorphisms in the PRNP promoter region have an influence on susceptibility to BSE. However, breed-specific differences exist that need to be accounted for when analyzing such data.
Mexican and Peruvian hairless dogs and Chinese crested dogs are characterized by missing hair and teeth, a phenotype termed canine ectodermal dysplasia (CED). CED is inherited as a monogenic autosomal semidominant trait. With genomewide association analysis we mapped the CED mutation to a 102–kilo–base pair interval on chromosome 17. The associated interval contains a previously uncharacterized member of the forkhead box transcription factor family (FOXI3), which is specifically expressed in developing hair and teeth. Mutation analysis revealed a frameshift mutation within the FOXI3 coding sequence in hairless dogs. Thus, we have identified FOXI3 as a regulator of ectodermal development.
Background There is accumulating evidence in studies of allergic diseases in humans and dogs that environmental experiences during the first months of life can influence the development of allergic disease. No prospective study has evaluated this in veterinary medicine. Hypothesis/Objectives To assess early‐life risk factors for canine atopic dermatitis (cAD) and estimate its heritability. Animals A West Highland white terrier birth cohort (n = 107) followed up to three years of age recording the development of cAD. Methods and materials The effect of environmental factors [house dust mites (HDM), hygiene, feeding, lifestyle] and early‐life determinants [breeder, mode of delivery, birth season, sex, litter size, early‐life immunoglobulin E (IgE) levels] were assessed, using Stata SE 15.1 statistical analysis. Heritabilities were estimated using the R program packages MCMC glmm and QG glmm . Results Maternal allergic status [ P = 0.013, odds ratio (OR 3.3)], male sex ( P = 0.06), mode of delivery ( P = 0.12), breeder ( P = 0.06), presence of HDM ( P = 0.11) and environmental hygiene level ( P = 0.15) were identified as possible influence factors by bivariate analyses. In the multivariate analysis the male sex was significantly associated with the development of cAD in the offspring ( P = 0.03, OR 2.4). The heritabilities on the observed scale were 0.31 (direct), 0.04 (maternal genetic effects) and 0.03 (maternal permanent environmental effects). Conclusion and clinical importance These results suggest that several environmental factors could influence the development of cAD but clearly demonstrate the genetic influence of the individual and the dam. Further studies are needed to identify specific environmental factors, which could be potential targets for primary disease intervention.
The introduction of livestock species in Europe has been followed by various genetic events, which created a complex spatial pattern of genetic differentiation. Spatial principal component (sPCA) analysis and spatial metric multidimensional scaling (sMDS) incorporate geography in multivariate analysis. This method was applied to three microsatellite data sets for 45 goat breeds, 46 sheep breeds, and 101 cattle breeds from Europe, Southwest Asia, and India. The first two sPCA coordinates for goat and cattle, and the first sPCA coordinate of sheep, correspond to the coordinates of ordinary PCA analysis. However, higher sPCA coordinates suggest, for all three species, additional spatial structuring. The goat is the most geographically structured species, followed by cattle. For all three species, the main genetic cline is from southeast to northwest, but other geographic patterns depend on the species. We propose sPCA and sMDS to be useful tools for describing the correlation of genetic variation with geography.
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