Single 5’green-3’red Hybrid Gene in Protanopia

Purpose: To disclose the structure of visual pigment gene for a protanopia with specific variation.Methods: Exon 5 fragments of the red andgreen visual pigment genes from the protanopia with specific varnation as well as controls were amplified by poly-merase chain reaction (PCR). The PCR products were put through heteroduplex-SSCP analysis and PCR-RFLP (restriction fragement length polymorphism) analysis to clarify the specific variation. The specific variation of the exon 5 DNA fragment from the protanopia was identified by sequencing.Results: A novel 5’green-3’red hybrid gene fragment without the normal red and green visual pigment gene was discovered in the protanopia. He should only have a single visual pigment gene, 5’green-3’red hybrid gene, on his X chromosome. The fusion point is between codon 285 and codon 296 in exon 5. Conclusion : Unequal intragenic recombination may occur in exon 5 as well as its upstream. A 5’green-3’red hybrid gene may present independently on the X chromosome without ac