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OPN1SW
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<p>Blue-sensitive opsin is a <a href="/facts/Protein/Jxmagu3E">protein</a> that in humans is encoded by the <i>OPN1SW</i> <a href="/facts/Gene/e1swwPY6">gene</a>. The OPN1SW gene provides instructions for making a protein that is essential for normal color vision. This protein is found in the retina, which is the light-sensitive tissue at the back of the eye. </p><p>The OPN1SW gene provides instructions for making an opsin pigment that is more sensitive to light in the blue/violet part of the visible spectrum (short-wavelength light). Cones with this pigment are called short-wavelength-sensitive or S cones. In response to light, the photopigment triggers a series of chemical reactions within an S cone. These reactions ultimately alter the cell's electrical charge, generating a signal that is transmitted to the brain. The brain combines input from all three types of cones to produce normal color vision. </p>