Search

Canine Degenerative Myelopathy is a late onset recessive autosomal disease characterized by a progressive ascending degeneration of the spinal cord. Two causal mutations are associated with this disease: a transition (c.118G>A) in exon 2 of the SOD1 that was described in several breeds and a transversion (c.52A>T) in exon 1 of the same gene described in Bernese Mountain dogs. The aim of this study was to understand the impact of the SOD1:c.118G > A mutation by genotyping a population of German Shepherd dogs in Brazil. A PCR-RFLP approach was used to genotype 97 healthy individuals belonging from the Northeast (Bahia and Pernambuco states) and South (Santa Catarina state) regions of Brazil. A total of 95 individuals were successfully genotyped resulting in an observed genotype frequency (with 95% confidence interval) of: 0.758 (0.672–0.844), 0.242 (0.156–0.328) and 0.000 (0.000–0.000) for “GG”, “AG” and “AA” genotypes, respectively. To our knowledge, this is the first attempt to describe the presence of the “A” allele associated with CDM (SOD1:c.118G > A) in German Shepherd dogs in Brazil and, as such, these results contribute toward important epidemiological data in this country and to the knowledge of the distribution of the aforementioned mutation worldwide.

Dermatosparaxis, also known as Ehlers-Danlos syndrome, is a recessive genetic disorder characterized by defects in collagen production, leading to skin fragility and delayed wound healing. In sheep this disease is associated to a transversion c.421G > T located on exon 2 of the gene ADAMTS2 and presents a special importance for the White Dorper breed. This study aims to identify carriers for the mutation associated with dermatosparaxis in Brazilian White Dorper herds and also to better understand the origin and the possibility of dissemination of this disease combining molecular and genealogical approaches. Genotyping by PCR-RFLP revealed the presence of seven out 66 heterozygotes, resulting in an estimated frequency of 5.3% for the dermatosparaxis associated allele in Brazilian White Dorper sheep. Pedigree analysis permitted the identification of two separate groups of individuals carrying the dermatosparaxis associated allele, one represented by descendants from individuals imported from South Africa and the second originated from animals imported from Australia. These findings suggest that the implementation of a program aiming to eradicate/control of dermatosparaxis in Brazilian White Dorper sheep is needed and the success of this strategy initially depends on the utilization of a molecular testing to detect carriers.

The Ovis aries species is phenotypically diverse and it is bred around the world for meat, milk and wool production. In the 1980s, small farmers in the semi-arid region of Pernambuco, Brazil, initiated the introgression of genes from Santa Inês and Bergamácia breeds in their local sheep of undefined breed, and the selection of individuals in an unstructured form, giving rise to an ecotype with unique characteristics called Berganês. The aim of this study was to perform genetic structure analysis of the Berganês ecotype population on farms in the state of Pernambuco using the Illumina® BeadChip OvineSNP50 high density chip as a way of increasing knowledge about the ecotype. Animals from seven farms were genotyped, totaling 96 animals (17 males and 79 females). Of the 54,241 Single Nucleotide Polymorphism (SNPs) found, we elected the ones with GenCall Score > 0.5, Hardy-Weinberg equilibrium (significance at 0.01) and lower allele frequency (MAF) > 0.2. In addition, only SNPs located on the autosomal chromosomes were maintained, according to version 4.0 of the sheep genome, with 39,250 SNPs being selected. The observed and expected mean heterozygosity values were, respectively, 0.37159 and 0.37943. The F statistics found were: FIS = 0.02622, FST = 0 and FIT = 0.02394. Most of the variability found (97.61%), which was estimated by AMOVA, is uniformly distributed within the herds and the Principal Component Analysis (PCA) did not allow the visual identification of a substructure considering herds, sex or phenotypic characteristics (coat color, ear size and insertion, and head morphology). Thus, the genetic variability presented in the animals of the Berganês ecotype is distributed homogeneously among the herds analyzed. Therefore, the genetic characterization presented here represents a key point in the creation of conservation plans and breeding programs, improving the efficiency of selection processes and the selection of breeders.