Molecular Investigation on DNA-PKcs Gene and Identification of SCID Carriers among Iranian Arabian HorsesUsing a Test Based on PCR

Investigation of the SCID mutant allele in Turkish Arabian horses reared in some private farms of the Eskişehir region in Turkey

“…Several previous genetic studies have investigated the five nucleotide deletion in the DNA-PKcs gene using primers that yield a PCR product of 521 bp [25], 259 bp [15], 235 bp [16], 179 bp [10], 174 bp [22], 169 bp [8,26], 163 bp [1,9,19,27], 162 bp [11], and 135 bp [13,17] in different Arabian horse populations.…”

“…To detect wild and mutant SCID alleles, the amplified PCR products were electrophoresed on 10% [10], 8% [13,15], and 6% Polyacrylamide gel [8,27], 4% agarose gel [17], or capillary electrophoresis [9,11,16,19]. In addition to electrophoresis, sequencing analysis could be performed to identify the genotypes of a population in terms of the presence/absence of SCID mutant alleles, as in these studies [1,25].…”

“…In addition to electrophoresis, sequencing analysis could be performed to identify the genotypes of a population in terms of the presence/absence of SCID mutant alleles, as in these studies [1,25]. The studies that investigated SCID in Arabian horses in the literature were summarized in Table. The SCID mutant allele was not observed in Arabian horse populations in Poland [18], Romania [16], Slovenia [17], Latvia [27], Iran [15], Syria [14], Ukraine [13], Egypt [1,28], or Turkey [19]. Conversely, the SCID mutant allele was identified in Arabian horse populations in the following prevalence: 8.4% in the USA [8], 2.8% in England [9], 1.5% in Brazil [10], 6.4% (in the year 2004) and 3.4% (in the year 2009) in South Africa [12], 5.6% in Morocco [11], 1.6% in Iran [26], and 0.4% in Poland [25].…”

“…After using diagnostic genetic testing, the frequency of the SCID mutant allele in South Africa was reduced from 6.4% in 2004 to around 3.4% in 2009 [12]. On the other hand, while the SCID mutant allele was not found in Poland in 1999 [18] or in Iran in 2011 [15], studies performed later showed that the frequencies of SCID carrier horses were determined as 0.19% [25] and 0.8% [26] in Poland in 2015, and Iran in 2017, respectively. According to Arabian Horse Association, from the start of testing in 1997 through December 31, 2011, a commercial testing company has tested >10,600 horses with a frequency of 15.7% SCID carriers and 0.3% SCID affected [29].…”

“…Among Arabian horse populations tested using molecular methods, the SCID mutant gene was detected in the USA [8], the UK [9], Brazil [10], Morocco [11], Egypt [1], and South Africa [12], but could not be detected in Ukraine [13], Syria [14], Iran [15], Romania [16], Slovenia [17], Poland [18], or Turkey [19]. There was only one study on SCID in Turkish Arabian horses.…”