Epsilon Archive for Student Projects

Abstract

Equine sarcoids (ES) are the most common skin tumors in equids all over the world. No universal treatment is yet available and the aetiology of the disease is not yet fully understood. Though, it is believed to be a multifactorial disease in which both genetic and infectious factors have been implicated. Association between ES and certain serotypes in the Major Histocompatibility Complex (MHC) region has previously been demonstrated and DNA from Bovine Papillomavirus (BPV) type 1 and 2 in and around equine sarcoid tumours has also been detected.
The aim of this study is to further characterize the molecular genetic background of the susceptibility of ES with the main focus on the MHC-region. The high resolution and accuracy of microsatellite analyses may complement earlier serological studies.
A total number of 78 horses were included in the study. 26 of these were classified as ES-affected by histological analysis. 32 of the horses were Swedish Warmbloods and 16 of these were ES-affected. 12 microsatellites in the MHC-region, including all three classes of MHC, as well as two microsatellites on chromosome 23 were tested for differences in heterozygosity and allele frequencies, occurrence of haplotypes as well as length of consecutive homozygous regions between cases and controls.
The majority of the markers with significant results are located in MHC class II. Significant results were also observed for one marker located on chromosome 23. Longer consecutive regions of homozygous markers were observed in cases than in controls indicating a disadvantageous effect. The genetic profiles of horses affected with Equine Sarcoids are different from that of non-affected horses. In addition, the results implicate breed differences in the genotypes of the horses included in the study. Interestingly, this study also indicates protective effects of certain alleles and haplotyps towards the development of ES.