X monosomy in the endangered Kiso horse breed detected by a parentage test using sex chromosome linked genes and microsatellites.

A routine parentage test as part of a conservation program for Kiso horses identified a possible sex chromosome anomaly in a 7 months-old filly because of an aberrant result using LEX3, an X-linked marker. We then analyzed X-linked markers (LEX26, TKY38, and TKY270), Y-linked markers (Eca.YH12, Eca.