title: Nucleotide polymorphisms upstream of the X-chromosome opsin gene array tune L:M cone ratio.
abstract: In support of the long-held idea that cone ratio is genetically determined by variation linked to the X-chromosome opsin gene locus, the present study identified nucleotide differences in DNA segments containing regulatory regions of the L and M opsin genes that are associated with significant differences in the relative number of L versus M cones. Specific haplotypes (combinations of genetic differences) were identified that correlated with high versus low L:M cone ratio. These findings are consistent with the biological principle that DNA sequence variations affect binding affinities for protein components of complexes that influence the relative probability that an L versus M opsin gene will be silenced during development, and in turn, produce variation in the proportion of L to M cones.
authors.affiliation: Department of Psychology, Wabash College, Crawfordsville, Indiana, USA.
authors.forename: Karen L
authors.initials: KL
authors.lastname: Gunther
authors.forename: Jay
authors.initials: J
authors.lastname: Neitz
authors.forename: Maureen
authors.initials: M
authors.lastname: Neitz
mesh_terms: D001483:Base Sequence; D044383:Black People / Q000235:genetics; D041321:Chromosomes, Human, X / Q000235:genetics*; D004247:DNA / Q000235:genetics / Q000302:isolation & purification; D017931:DNA Primers; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction; D020641:Polymorphism, Single Nucleotide; D017949:Retinal Cone Photoreceptor Cells / Q000502:physiology*; D017299:Rod Opsins / Q000235:genetics*; D044465:White People / Q000235:genetics
chemical_list: D017931:DNA Primers; D017299:Rod Opsins; D004247:DNA