From: Tim 12/04/2001 12:18:55 Subject: Husky's Different Coloured Eyes post id: 278076 As far as I was aware, in normal circumstances the genes of a father and mother go towards making up the characteristics of their offspring. This generally includes skin, hair and eye colour etc.. Why then would the majority of Siberian Huskys have one blue and one brown eye?? From: Zardoz ® 12/04/2001 12:44:09 Subject: re: Husky's Different Coloured Eyes post id: 278115 It is indeed possible for people to have eyes of two different colours. It's observed fairly frequently in some inbred strains of dogs, like malamutes (husky like dogs), but is rare in humans. A few famous examples are : David Bowie, Kiefer Sutherland and Christopher Walken. I didn't find any diseases associated with this condition, so aside from social effects I guess it's perfectly harmless. With the advent of coloured contact lenses, now it's possible for anyone to have two different coloured eyes. I wish I could explain to you how or why this occurs naturally, but I can't find any relevant research, nor even mention of the condition in ophthalmological texts. The basic biology of eye colour is quite simple: eye colour is the result of production of the brown pigment melanin in the cells of the iris. The amount of melanin determines eye colour; lots of melanin produces brown eyes, some melanin produces hazel eyes, and little melanin produces blue eyes. (Green eyes weren't mentioned, but I suspect they are a combination of blue with another pigment.) Genes controlling the production of melanin therefore influence eye colour. An interesting possibility that could account for eyes of different colour in the same individual is somatic mosaicism. This is probably easier to describe than explain: in multicellular organisms, every cell in the adult is ultimately derived from the single cell fertilised egg. Therefore every cell in the adult normally carries the same genetic information. However, what would happen if a mutation occurred in only one cell at the two cell stage of development? Then the adult would be composed of two types of cells: cells with the mutation and cells without. If a mutation affecting melanin production occurred in one of the cells in the cell lineage of one eye but not the other, then the eyes would have different genetic potential for melanin synthesis. This could produce eyes of two different colours. http://www.madsci.org/posts/archives/dec96/836369191.Ge.r.html From: J.F. ® 13/04/2001 9:17:29 Subject: re: Husky's Different Coloured Eyes post id: 278696 In dogs, this may be due to the "merle" or "harlequin" genes. There is a pedigreed cat breed called "Odd-eyed white" AFAIK, it is related a little to albinism + the role of melanocytes. I posted a lot of info on this in other threads, especially the Albino child thread. I cannot post links yet, so I recommend that you use "edit-find" in the LH box. This forum is un-moderated. The views and opinions expressed are those of the individual poster and not the ABC. The ABC reserves the right to remove offensive or inappropriate messages.