A chromosome inversion near the <i>KIT</i> gene and the Tobiano spotting pattern in horses

Abstract

Tobiano is a white spotting pattern in horses caused by a dominant gene, <i>Tobiano</i><i>(TO)</i>. Here, we report <i>TO</i> associated with a large paracentric chromosome inversion on horse chromosome 3. DNA sequences flanking the inversion were identified and a PCR test was developed to detect the inversion. The inversion was only found in horses with the tobiano pattern, including horses with diverse genetic backgrounds, which indicated a common genetic origin thousands of years ago. The inversion does not interrupt any annotated genes, but begins approximately 100 kb downstream of the <i>KIT</i> gene. This inversion may disrupt regulatory sequences for the <i>KIT</i> gene and cause the white spotting pattern. This manuscript is accompanied by supplemental figures S1, S2 and S3, as well as supplemental Tables S1 and S2 (www.karger.com/doi/10.1159/000112065). The DNA sequence generated in this work has been submitted to GenBank under the following accession number: EF442014.