What is a Tetrachromat?
The science of vision is complex and our understanding of how we “see,” interpret and process our environment conveyed by visible light is evolving. The scientific study of visual perception spans many scientific disciplines: genetics and molecular biology, neuroscience, psychology and cognitive science.
Scientists have been able to map and identify the physical components contributing to sight and the pathways of the visual system in the brains of humans and animals, but they are still exploring the interaction between genes and the outcome or expression of those genes as they relate to visual perception.
Infrequently, an individual may have a specific gene mutation that ultimately provides a genetic potential for the expression of four distinct classes of retinal photopigments, whereas most people have three retinal photopigments. Individuals who have four retinal photopigments are said to have the genes or genetic basis for retinal tetrachromacy (tetra = four, chroma = color). Concetta is such an individual whose genetic analysis in late 2012 demonstrated a genetic sequence consistent with the specific gene mutation permitting the expression for four retinal photopigments.
While the science of how the nervous system translates and processes the signaling and information derived from these four retinal photopigments is under intense debate, we do know, and see from Concetta’s paintings as well as from early perceptual investigations she has undergone, that she has exceptional color processing compared to normal controls. Further study into her color perception and processing is the topic of on-going and intense research.
Latest Scientific Research from Dr. Kimberly Jameson from University of California’s Institute for Mathematical Behavioral Sciences ~ Concetta is Subject CA
This article uses multispectral techniques to investigate color processing in two individuals possessing photopigment genotypes allowing potential human tetrachromacy. In our investigations we measure spectral reflectances from empirically reproduced color sensations of potential tetrachromat observers, and investigate color processing basis functions underlying the observed set of tetrachromat spectra. Our investigations provide new empirical and quantitative methods for estimating trichromat individual’s personalized spectral sensitivities, and, as shown in one poten- tial tetrachromat examined, permit estimation of cone response sensitivities for cases that may not conform to the kind of stan- dard dimensional solutions typically associated with trichromat models. Read the full article.
Welcome to the world of Subliminal ColorTM by Concetta Antico …
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Art and the Curiosities of Color Vision
Kimberly A. Jameson University of California, Irvine, CA, USA
Read the article
An Update on the Latest Scientific Research on Concetta’s Color Perception
Dr., Kimberly Jameson, University of California’s Institute for Mathematical Behavioral Sciences, continue to pursue assessment of Concetta Antico as a research participant of great interest.
New research results in which Concetta Antico has been involved as a research participant, bear on issues relating to individual differences in color processing. Dr. Jameson recently presented new findings in a research colloquium to the faculty at Institute of Mathematical Behavioral Sciences at UC Irvine, and receiving positive support for the new findings, and will be presenting again at the Munsell2018.org conference (see attached abstract). Jameson’s new results are the most recent in a several years effort by which she has learned much new information about the ways expert observers differ in color processing from, for example, a standard normal observer. The issue of individual variation in color perception, and how it relates to what is know about a standard normal form of color processing, is, of course, something that is central to the study of comparative color perception and artistic processing of visual scenes, and is of great interest to the art collector and enthusiast community. Dr. Jameson believes that her team of researchers and the collaborative work they have engaged in with Concetta Antico, presents an exciting opportunity for extending impact on developing approaches for personalized data displays and color space models. Dr. Jameson’s research team have a very solid and productive collaborative relationship with Concetta Antico — who has voluntarily participated in our research investigations for several years now. Additional findings on Antico’s tetrachromatic processing potential are expected in Fall 2018
The Genes for Color Vision
The DNA of every normal-vision human observer includes inherited “opsin genes” which produce the visual pigments responsible for human color vision. Some of these visual pigments – for example, those sensitive to longer-wavelength and medium-wavelength light from the visible electromagnetic spectrum – arise from genetic sequences on the X-chromosome and are inherited in a recessive manner, while others that are sensitive to short-wavelengths of light are inherited in an autosomal dominant pattern via chromosome 7.Three human “photo”-pigment classes are typically involved in “photopic”, or daylight, processing of visual stimuli. In a normal retina, these photopigments reside within light-sensing “cone” cells that populate a retinal mosaic that includes “Long-wavelength sensitive”, “Medium-wavelength sensitive”, and “Short-wavelength sensitive” cone cell classes, (abbreviated “L-” “M-”, and “S-cones”).During the normal process of opsin gene inheritance and development, changes in the “usual” opsin gene sequences can occur. For example, mutations, deletions, and rearrangements of the genes that encode human L- and M- opsins can result in deficiencies in red-green color discrimination for some individuals. Not all mutations are bad, however, and some opsin gene sequence changes can modify the response properties of L- and M-cone cells while having no deleterious consequences for the perceptual processing of environmental color stimuli.Infrequently an individual may have specific opsin gene mutations that ultimately provide a genetic potential for the expression of four distinct classes of retinal photopigments. Such individuals can be said to have the genes, or the genetic basis, for retinal tetrachromacy.
What exactly are the genes, and what is the genetic basis, for retinal tetrachromacy?
While the length of the L- and M-opsin genes may seem great (~14,000 base pairs and ~12,030 base pairs, respectively), it is perhaps surprising that L- and M-opsin gene sequences differ by only15 loci along their protein coding gene sequences.This is especially interesting from a perceptual standpoint since those 15 coding sequence changes alone are responsible for a ~30 nanometer (nm) shift in cone sensitivity that is characteristic of an L-cone class “red” signal peak compared to that of an M-cone “green” signal peak. Interestingly, the majority of this 30nm difference in peak sensitivities between the normal red and green visual pigments is accounted for by differences in the genetic sequence at positions 180, 277, and 285.Indeed (and this is important for understanding potential tetrachromacy), the most influential of these three sequence positions involves single-nucleotide substitutions (or SNPs) at codon 180 of Exon 3. That is, at codon 180 a photopigment encoded from an Alanine allele has a maximal absorption that is shifted approximately 5nm towards the shorter wavelengths compared to the absorption peak of the “normal” form of the L-cone pigment encoded by a Serine variant (Merbs & Nathans, 1992, Asenjo et al., 1994).The frequency of opsin gene variations differs across the general human population, but it is estimated that in some groups L-cone pigment genes encode Serine 56% of the time and encode Alanine 44% of the time at position 180 (Gegenfurtner & Sharpe, 1999). The stable frequency with which the L-opsin codon 180 mutation is present in humans may suggest it is not likely a deleterious mutation of the opsin gene sequence.An individual possessing an L-opsin codon 180 tetrachromat genotype is special in that they possess opsin genes that encode both Serine and Alanine variants of the L-cone photopigment.