Pyrosequencing results for 14 X-linked genes in female horse chorionic girdle trophoblast samples. Plotted are allele-specific expression percentages in horse day 33 chorionic girdle samples quantified by pyrosequencing in five female horse samples. (Green) Horse reference allele; (orange) alternative allele. Uninformative homozygous loci are not shown. We observed variable biallelic expression for all 14 genes rather than preferential maternal expression, suggesting random X inactivation in horse placenta. Within genes, we also observed the cis-eQTL effect (EIF1AX, RGAG4, RBMX, and FLNA). The horse X chromosome ideogram was drawn from the work by Bowling et al. (1997).
