SERINE ALANINE AMINO-ACID POLYMORPHISM OF THE L-CONE AND M-CONE PIGMENTS - EFFECTS ON RAYLEIGH MATCHES AMONG DEUTERANOPES, PROTANOPES AND COLOR NORMAL OBSERVERS

In a first experiment, groups of deuteranopes and protanopes were char acterized psychophysically by the slopes of regression lines fitted to yellow intensity settings from their Rayleigh matches. In a second ex periment, color normal male subjects were characterized by their 2 and 8 deg Rayleigh match points. All subjects had been previously charact erized genetically by the presence of the amino acid serine or alanine at position 180 on their L cone or L/M hybrid opsins. Dichromats and color normal subjects with serine had greater sensitivity to the red p rimary than did those with alanine. Calculations based on psychophysic al results suggest that the substitution of serine by alanine in the L cone opsin or L/M hybrid opsin produces a shift in lambda(max) of the expressed pigment toward shorter wavelengths by an amount varying bet ween 2.6 and 4.3 nm, with the shifts in lambda(max) for the dichromats being larger than those for the color normal subjects.