As readers of my gay quad stories know, Raith, ceramist, artist and ex-con, sees, not the million or so colours that most of us see, but ten million. He’s described as a tetrachromat. But should he be? Tetrachromats are women. Men aren’t supposed to have that sort of vision. Phil, the doctor in the quad, is explaining why not to the other three:
“You’ve heard of rods and cones?” There were nods of affirmation. “Rods for light intensity. Cones for colour discrimination. Most people have three functioning sets of cone cells. Each set responds to a different range of colours. One set deals with reds. One deals with blues. One with greens. You see other colours in combination.”
“How?” asked Raith. “Where’s the yellow? Blue and yellow make green.”
“That’s paints, love. Light works differently.”
“So, three sets of cone cells. Trichromatic vision. Now, there’s a gene called the optic gene. It affects the pigments in the eye that respond to light. Sometimes the optic gene undergoes mutation. The gene is on the X chromosome.” Phil waited.
“Ah,” said Mike, as the penny dropped. “Women have two X chromosomes. Men have one X and one Y.”
“Exactly. So a woman can receive the mutated gene from both parents. A man can only receive it from one. The usual result in a man is colour blindness. A woman who has the mutation on both chromosomes ends up with four functioning sets of cone cells instead of the usual three. Tetra: four. That fourth kind of cone results in greater colour intensification and greater colour discrimination. Tetrachromatic vision.”
“But I’m a man!” Raith said. “I’m bi though. Could that affect it?”
“That’s your orientation, Raith. Not your gender. Orientation and gender are different,” said Ross.
“Yeah, but maybe it’s affected my genes. Is being bi or gay or whatever genetic, Phil? Maybe I’m gender fluid. Could I be?”
“Your first question- I wouldn’t like to say. Years ago, I did a lot of research into being gay – just trying to understand myself – or accept myself – but both I and the science have moved on. It’s moving forward every day. Your second question – no. You’ve never given any indication that you wake up uncertain of your gender. ”
“For God’s sake, Raith. You might go in for a bit of cross dressin’, but that’s nuthin’ to do with your gender. Just your lousy fashion taste.”
“Ha ha. Very funny. So I’m just a bisexual male who, for some reason, sees like women see. Can we get back to my being a terra- thing, please?”
“Tetra, idiot. Not terra. Though thinkin’ about it…”
“You shite! Tetra then. How have I got it if I can’t have got it through the mutation?”
“Well, ” said Phil, “there must be other reasons, though they’re not fully understood yet. One thing is that tetrachromacy occurs in other species regardless of gender. Birds, fish…it’s almost as though humans have lost a gene which was common in the past.”
“You mean it’s the rest of us who’ve mutated – not Raith!” Mike suggested, grinning.
“It isn’t funny. But is that what you mean?”
“Perhaps you just haven’t evolved as much as the rest of us have.”
“Fuck you, Mike!”
“It’s sort of what I mean, yes. I don’t follow the research in any detailed way. It’s a very different branch of medicine from mine.”
“Medicine? Am I ill then?”
“No. Bad choice of words. It involves a different aspect of the human body from the one I’m usually acquainted with.”
“Phil’s used to lookin’ up people’s bums not lookin’ into their eyes, Raith. As he says – a different aspect.”
“I know that there can be a lot of variation in the properties of the opsin gene. I do know of one study which suggests that around eight per cent of males presumed to be colour ‘normal’ have sufficiently big variants that they could exhibit extended colour perception relative to ‘normal’ trichromatic males. They might have four photopigments present instead of the usual three.”
“Eight per cent is a lot. Where are all these men? Not in the art world, obviously,” said Ross. “I only know of one other tetrachromatic artist – an Australian woman, Concetta Antico.”
“It’s thought that two to three percent of women have the required mutation. That’s millions of women. Presumably, the gene doesn’t get switched on for some reason. It must be the same with the men. There’s another possibility, though. I mentioned the rods before. It’s thought that at low light intensities, the rod cells may contribute to colour vision. They’d give a small region of tetrachromacy in the colour spectrum. The greatest sensitivity would be at the blueish green wavelengths.”
“That is interesting,” Ross agreed. “Raith likes to paint water. He chooses to live in this dark and gloomy part of England. Even at the height of summer, light levels are hardly Mediterranean.”
“And we often get worried about you gettin’ lost on the moors because you’re still out there paintin’ long after dusk,” said Mike….
( text © Jude Tresswell, 2018)
So, it seems to me that Raith could, as he puts it, have this tetra-thing. Concetta Antico is a real painter. You can see her paintings on the net. When ‘normal’ tri-coned folk like me look at them, they seem no different from anyone else’s in some ways. That’s because my eye doesn’t distinguish the colours, doesn’t discriminate between them. In other ways they do look different. They are bright. Astonishingly bright. Imagine looking at peacock and kingfisher feathers – and seeing such intensity everywhere. I would think it’s overwhelming sometimes, but perhaps tetrachromats are simply used to it. It’s their normal way of seeing the world.
If readers are interested in following this up: see Richer color experience in observers with multiple photopigment opsin genes Jameson. Highnote and Wasserman, Psychonomic Bulletin & Review, 2001, 8 (2) 244-261. It is a Wiki link. Also Sjoberg, M.Neitz, Balding and J.Neitz, 1998 in Vision Research, 38, L cone pigment genes expressed in normal vision. This is referred to in Jameson et al’s research but I had difficulty accessing the original.
For less strenuous reading, Raith and co are the protagonists of Badge of Loyalty (pub. February 2018) and Polyamory on Trial (pub. August, 2018). Both are by Jude Tresswell and are available as paperback and e book from the usual distributors or from http://www.rowanvalebooks.com .