Genetic Monitoring for Severe Combined Immunodefici ency Disease (SCID) Carriers in Arabian Horses of Iran

Abstract

SCID is a lethal genetic autosomal recessive disord er that has been observed in humans, dogs, mice, and horses. Affected animals are incapa ble of generating specific antigens for immune responses needed to protect them from infect ious diseases. The frequency of affected recessive allele varies in different regio ns so that the outcome of normal breeding with carriers of recessive alleles is differently d istributed. Little information is available for SCID carriers in Iranian horses to prevent carr iers breeding. In this study, the occurrence of the SCID alleles was tested in repres entative samples of Persian Arabian (or Asil) horses. Blood samples were collected from 244 Arabian horses in eight provinces of Iran. The ARMS-PCRs were used for the first time to identify SCID carriers, based on three distinguishing primer pairs. Each sample was used in two separate PCRs with a common forward primer. The two reverse primers diff ered in their 3 ′ end: one reverse primer could pick the wild-type allele while the ot her could pick the mutant allele with a 3 ′ end deletion. An internal control (HMS02 locus) wa s used in both reactions to verify whether the amplifications worked correctly. The re sults showed a mutated allele frequency of 0.8% in the Arabian horse population o f Iran. This is the first report identifying SCID carriers’ frequency among Arabian horse population in Iran. Keywords : Arabian Horses, ARMS-PCR, DNA-PK CS , SCID.