Protanopia refers to the inability to perceive red color. Protanomaly refers to an impaired ability to perceive red color. Impaired green color perception leads to deuteranopia and deuteranomaly. Males with a deleted green pigment gene on the X chromosome result in deuteranopia or green color vision deficiency. A crossing over between mismatched gene segments of both the colors results in a chimeric gene. It involves joining of a part of the green pigment gene with the part of the red pigment gene. When the 5’ end of the green pigment gene combines with the 3’ end of the red pigment gene to form a chimera, the crossing over point occurs in either of the two places. The crossing over point occurring near the 5’ end leads to a chimeric gene expressing red pigment. Hence, it leads to green blindness or deuteranopia. If the crossover point occurs near the 3’ end, the green pigment gene predominates. Hence, it leads to deuteranomaly. Consider another case of color vision deficiency. A chimeric gene consists of a red pigment gene at 5’ end and green pigment gene at 3’ end. Also consider two cases of unequal crossing over. If the crossover point is near the 5’ end, the green pigment gene predominates. The red pigment gene does not remain. Hence, it leads to red-blindness. If the crossover point is near the 3’ end, it results in protanomaly.