Figure 1. RT–PCR analysis of Eph and ephrin expression in 20 WG fetal human retina. A: We found low levels of amplification of Eph-A5, and (B) no amplification of ephrin-A2 and -A5. Eph and ephrin PCR primers are listed in Table 1. PCR products were visualized with electrophoresis using ethidium bromide staining on a 1% agarose gel, and used to generate DIG labeled riboprobes for Eph-A5, -A6, -B1, -A7, and ephrin-A1, -A4, and -B2.