![]() Significant differentiation between the combined German shepherd dog population and the outbred dogs illustrates the effects of selection and genetic drift on the breed since its establishment just over 100 years ago. Non-significant population differentiation between the ancestral German and derived South African populations indicates sufficient contemporary gene flow between these populations, suggesting that migration resulting from the importation of breeding stock has mitigated the effects of random genetic drift and a population bottleneck caused by the original founder event in South Africa. ![]() The breed is characterised by only a moderate loss of genetic diversity relative to outbred dogs, despite originating from a single founding sire and experiencing extensive levels of inbreeding throughout the history of the breed. Both the imported and locally-bred German shepherd dogs exhibited similar levels of genetic diversity. ![]() These data were quantified by comparison with typically outbred mongrel or crossbred dogs. Microsatellite marker analyses of 15 polymorphic canine loci were used to investigate measures of genetic diversity and population differentiation within and between German-bred and South African-bred German shepherd dogs. Thus, in parallel with the morphological variation displayed by breeds, purebred dogs commonly express genetic defects as a result of the inbreeding associated with artificial selection and the reduction of selection against disease phenotypes. © 2012 Veterinary Radiology & Ultrasound.Ĭomparative population genetics of the German shepherd dog in South Africaĭirectory of Open Access Journals (Sweden)įull Text Available Modern breeding practices strive to achieve distinctive phenotypic uniformity in breeds of dogs, but these strategies are associated with the inevitable loss of genetic diversity. Imaging of the cranial thoracic spine, including T2-T3, is recommended for German Shepherd dogs with T3-元 neurological signs. ![]() Findings from this study indicated that German Shepherd dogs may be more likely than other large breed dogs to have spinal cord compression due to cranial thoracic disc herniations. The German Shepherd dog group had higher scores than the control group for compression (P = 0.0099) and herniation (P dog group, intervertebral discs T2-T3 and T4-T5 had an increased risk for compression and T3-T4 had an increased risk for compression and herniation. Twenty-three German Shepherd dogs and 47 other large breed dogs met inclusion criteria. For each dog and each disc space from T1-T9, three variables (compression, disc degeneration, and herniation) were recorded and graded based on review of sagittal T2-weighted images. Medical records at the Ontario Veterinary College were searched for German Shepherd dogs and other large breed dogs that had magnetic resonance imaging studies including the T1-T9 region. The purpose of this retrospective study was to compare cranial thoracic intervertebral disc herniations in German Shepherd dogs and other large breed dogs (control group). Gaitero, Luis Nykamp, Stephanie Daniel, Rob Monteith, GabrielleĬranial thoracic intervertebral disc herniations have been reported to be rare in dogs due to the presence of the intercapital ligament, however some studies have proposed they may not be uncommon in German Shepherd dogs. Comparison between cranial thoracic intervertebral disc herniations in German Shepherd dogs and other large breed dogs. ![]()
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