Length difference between equine ZFX and ZFY genes and its application for molecular sex determination.

we analyzed the sex chromosome-encoding ZFX-ZFY genes and tested molecular sexing using the amplification patterns of intron 9 of ZFX-ZFY in the horse.,the amplification of the ZFX-ZFY produced two distinct patterns, reflecting sexual dimorphism based on a length difference between the X and Y chromosomes. The amplification products from foals showed two distinct bands: one was common to all foals and mares, indicating that this band was amplified from ZFX, while the other was specific to some foals, indicating that it was from ZFY. The result based on the PCR assay was identical to the results of amplification of the Y chromosome-specific SRY gene and those of investigations of the phenotypic gender in three different horse populations.,we suggest that this PCR strategy for determining sexes by comparing the amplification patterns of ZFX-ZFY genes is a convenient and precise method for discriminating sexes in horses.