Talk:Leucism

Are

Are leucistic animals truly albino's? Everything I've read says that leucistic animals are lighter, but not truly albino's. Such as this story http://www.wcs.org/353624/whitegiraffe about a leucistic giraffe. Suppafly 18:12, 15 September 2005 (UTC)

Image added

I added an image showing Leucism in a Mallard duck
Wonko the Sane 19:44, 9 March 2007 (UTC)

human leucism

Is there a posibility that leucistic humans exist? My grandfather was a werry pale man who married much darker woman, and ended up with 4 sons 3 pale in different ways(one white hair and beard one pale skin)an one with dark hair and dark skin. my father was paleskinned but had blondhair and a red beard and marrried a spannish lokking woman, i to am extremly pale,what the f.. do i have?

I agree with the artical pertaining to humans. For I believe the first human was a black man and from him came all people of color including the white man. Our leaders will not discuss this issue. It is used but rarely in humans this LEUCISM. (JK)

There are different forms of spotting in humans, the Waardenburg syndrome and Piebaldism Kersti Nebelsiek 20:47, 1 April 2007 (UTC)

This is probably a case of it - http://www.thesun.co.uk/sol/homepage/news/3062547/Docs-to-study-black-couples-white-baby.html —Preceding unsigned comment added by 151.196.243.211 (talk) 03:41, 22 July 2010 (UTC)

Incorrect explanation

The explanation for what leucism is in this article is incorrect. Leucism is a catch-all term for result of defects in chromatoblast differentaition and/or migration from the neural crest. This results in either the entire skin, or patches of skin, having a lack or reduction in chromatophores (the cells that make pigment). [1] Since all chromatophore types differentiate from the same precursor cell type, this can effect all colours of pigment (since, if the cell isn't there, the pigment can't be made). This differs from albinism. Albinism only effects melanin production because it is a defect in key enzymes required for the process, but the cells are still present. The reason eyes are not usually affected in leucism is because the pigment cells from the eye do not come from the neural crest. However they are affected albinos because they use the same process to make the melanin. When i get the chance this week, i'll rework the entire article to try and make it accurate. In the meantime, i'm tagging it with {{incorrect}} and {{expert}} templates. Rockpocket 18:29, 18 July 2006 (UTC)

It is not completely true, that the eyes are not affected in Leucism. There are leucistic animals with red eyes, there are leucistic animals with blue eyes and there are leucistic animals with dark eyes - that differs because of the different genes, leucism may be due to.

Completely albinotic animals usually have red eyes (Allel c) - but not every animal with a form of albinism is completely albinotic and therefore there are partly albinotic animals with red, blue or darker eyes. Kersti Nebelsiek 20:41, 1 April 2007 (UTC)

For examples of leucistic Mice with red eyes, see: http://www.informatics.jax.org/searches/allele_report.cgi?markerID=MGI:104554 Kersti Nebelsiek 22:50, 10 April 2007 (UTC)

Chromatophore

To Rockpocket

I took your suggestion and looked at the Chromatophore article. It is very nice. I may do a clinically oriented article to dove tail with it when I get the chance.Snakevet2003 08:14, 10 December 2006 (UTC)

Sounds good. By the way, I reverted your recent edit regarding the skin microenvironment. I did so because it replaced an explanation for why there is a difference (genetically speaking) with a consequence of that. Still, I think some of your content above would benefit the article, you would just need to source it. Rockpocket 08:18, 10 December 2006 (UTC)

skin microenvironment.

Research done and reported by Bechtel in his book does explain why there is a difference. The difference is not due to the melanin producing cells not arising from neural crest, in fact, some embryologists will disagree with you about the melanocytes not being of neural crest origin as some consider all of the neuroectoderm to be of neural crest origin including the portion that forms the optic cup. However, be that as it may, if melanocytes from the eye are placed in the skin, they die. The problem is not due to the different develomental origins, it is due to the microenvironment of the skin. Furthermore, as I explained the transplantation of healthy chromatophores demonstrates the problem is not due to embryologic origin, but within the skin itself. I have deleted my explanation above, because I just found that others have apparently edited it and added both false and racially oriented material to it. This vandalism I cannot tolerate. Unfortunately this is the third time I have written something for wikipedia and had it changed in such a way as to be inappropriate and offensive. I think I will not submit anything further until wikipedia allows responses to be locked and unchangable.User:snakevet2003 23:05, 10 December 2006 (UTC)

Regarding the editing of your comments above, checking the edit history it doesn't appear to me that anyone edited your comments nevermind added "racially oriented material". The only edits to it were the automatic addition of a signature by a bot [2]. Could you elaborate on what you mean and I can take action against the culprits? Rockpocket 00:44, 11 December 2006 (UTC)

Eye Colour

The pink ('red') colour for which albinos are famed is not the colour of the retina but the colour of the iris, which lacks melanin also. Even in albinos, the pupil still looks black rather than red because the inside of the eyeball is dark, irrespective of whether the retina is as black as it would normally be. This needs correcting, please, somebody, but I'm not an expert so I'm not doing it.

Sapphirine 03:12, 17 December 2006 (UTC)Sapphirine

My understanding is that the red colour (which is actually pretty rare in human albinos) is from the blood vessels that line the retina and the iris. In the absence of a pigmented iris and a pigmented RPE, these vessels will be apparent. This give the pupil a red hue in the presence of light (everything looks black in the absence of light!) and the iris a red hue to the the light reflecting from the fundus being absorbed by the haemoglobin. I'll see if I can clarify. Rockpocket 03:32, 17 December 2006 (UTC)

Albino Cat. (This one is NOT leucistic. It's of a scientific paper, therefore I am shure.)

If you look at this albinotic cat, you see that the Iris looks pink and the pupil is a bit reddish too, because in the eye it is not as dark, as it should be. That is the reason why fully albinotic animals and people are half blind. Kersti Nebelsiek 16:14, 16 April 2007 (UTC)

The information presented by the snakevet guy is correct, and just for everyone's information, I believe that someone edited what he said with racial slurs. That happens a lot on this site, and that along with the large amount of disinformation in the articles is why I will not allow my students to use Wikipedia as a resource. Anyway, several experiments have been done on leucism, albinism and eye colour. I have read Reptile and Amphibian Variants by Bechtel and articles are out there on PubMed, or Scopus on the transplantation subject. Most of the published information indicates that the melanophore origin has no bearing, but it is a microenvironment issue. In fact, having done necropsies on many leucistic animals, I can tell you that they can have pigmented internal organs, while their skin is pigmentless. The melanomacrophages of the liver are also present in many leucistic animals. The origin of the melanophores in the internal organs is neural crest, yet they function. So at least in reptiles, the information stating that it is the origin of the cell that matters is absolutely WRONG. Transplanted melanophores or xanthophores from normal skin, do develop and function normally in albino skin, that is in the literature, look it up for yourself. If placed in leucistic skin, they perish. So in reptiles at least, it is a microenvironment issue, not origin of cells issue. There is also the annoying little fact, that it has not been established what the intraocular melanophores in reptiles arise from. It is an assumption that they do not arise from neural crest, but in truth, that is not established anywhere in the literature that I have been able to find.

As for the article itself, I would urge anyone to look up information on your own. I have generally noticed that this site has what one of my colleagues refers to as "territorial nerds" that will use the articles for their own opinion and support their arguments with a few citations and ignore other citations that do not agree. Once someone tries to change things and make the article more accurate, the territorial nerds come in and change everything back to the incorrect or incomplete information. I ran into this in another article with a person who eventually revealed he was a reptile hobbyist and would cite his article on Wikipedia when he gave talks to elementary schools, but the information was far from correct or up to date, and he would allow no one to change it. I get the feeling that may be the case here. --Vetpathol04 —Preceding unsigned comment added by 130.39.48.176 (talk) 16:10, 25 September 2007 (UTC)

Dr. Walden is back up

After a long while, Dr. Walden is back up. I had the opportunity to study under him at LSU and he is pretty amazing. He is a herpetopathologist. He has actually done quite a bit of research on reptile disease. He had a blog and members could ask him questions, but it shut down when the server crashed. It is now back up at a different location (http://veterinaryherpetologist.blogspot.com). He has actually put as his first post an explanation about leucism. Be warned though, he HATES wikipedia. He calls it the misinformation super highway's drunk lane. He also has the same discussion posted at hubpages, but this site will not allow me to post the address as a link, because someone at wikipedia has blocked hubpages so his discussion is hubpages.com/hub/Understanding-Reptile-Color-and-Correct-Color-Terminology.

He is quick to point out that 1)the use of the s sound (lusistic) is incorrect and lets people know you are poorly educated, 2) hypomelanism in birds is not the same as leukism, but many sites incorrectly label it as leukism, 3) many of the pictures in this article are incorrectly labeled as leukism, when they are actually pattern anomalies -- the pigeon on the article page is NOT leukistic, it has a pattern anomaly called the speckled pattern. If it were leukistic, the legs would not be the normal color, 4) studies show there is a mutation in the skin that causes some forms of leukism and other forms are caused by embryonic death of the pigment cells, but patches of white are NOT leukism, and these are probably another condition.

Well, he's wrong that the /s/ pronunciation is incorrect. It's the regular pronunciation--that is, the one expected from the orthography, and also the most common. He may prefer an alternate pronunciation, but his preferences don't define the language. That's like silly people saying, "it's not pronounced veyss, it's vahz. If you say veyss, you're a peasant." If herpetologists generally share his preference, then we can note just that. But it's incorrect to say that one pronunciation is "incorrect", and I will revert any claim that it is. Our job here is not to dictate language, but to document it.

There are many scientists who attempt to make Latinate words sound more Latin than standard literary English would have it. There's debate over whether this is snobbishness, a shibboleth for their education, an attempt to be more intelligible to an international audience, or just personal preference of no import. For example, some astronomers pronounce the Jovian moon Io "EE-oh" rather than the literary pronunciation of "EYE-oh". (Neither, of course, is the actual Latin pronunciation.) Most scientists don't really care, and work just fine with their colleagues who choose a different pronunciation. It's never "wrong" to use standard, educated English pronunciation. (And "leucism" is Greek, so if you want to sound educated, perhaps you should pronounce it properly: "LEF-kiss-m", not "LEW-kiz-m". kwami (talk)

Strongly concur on all of those points, Kwami, and can further confirm that after over 15 years involved with people in the herp pet trade (including breeders of snakes and others animals in which leucism is a commonly desired trait), I've heard "leuSISStic" probably 500 times, and "leuKISStic" precisely ZERO times. — SMcCandlish [talk] [cont] ‹(-¿-)› 05:16, 13 December 2009 (UTC)

I was going to mention the pigeon too, and I'm just some dumb guy :/ It's like calling the pied mutation leucistic, hehe.dumbguyhere —Preceding undated comment added 13:53, 5 March 2010 (UTC).

Source for expansion

• Cousins, D. (2007). "Albinism and leucism in primates". International Zoo News. 54 (3): 134–145.

I don't have time to add the material myself, but any editor may email me for a copy if needed. – VisionHolder « talk » 02:02, 28 July 2010 (UTC)

Etymology

Although the leuc(o)- affix is used in a great many medical terms, I don't see its use here as being "from medical terminology" but rather from the practice of using Latin and Greek in scientific discourse as a whole.Barndoorsentry (talk) 20:02, 29 September 2010 (UTC)

Eyesight

Does anyone know whether leucism can affect eyesight, in a similar way to albinism but to a lesser degree? I don't mean only in association with pink eyes (which according to the above can occur in leucistic animals), but also in animals with normal-looking eyes. Sorry for the following anecdotal basis... My cat is leucistic (according to my own assessment, but I am pretty sure) and I have always felt that his eyesight is worse than average (though it was much more evident when he was a kitten). If anyone can verify that there is a known correlation, then it should certainly be added to the article. Salopian (talk) 12:50, 2 January 2011 (UTC)

Explanation

I'm not seeing a genetic explanation in the article for this syndrome. I was shocked to learn that it could be found, not merely in mammals but in alligators and (in this article) birds. But why? I can appreciate that the specifics aren't known yet. But whatever is known should be here. DNA. Whatever. Student7 (talk) 00:23, 6 February 2011 (UTC)

Genetics of leucism

I am a breeder of Sugar gliders, and we frequently breed for the leucistic gene. I can only assume it works simmilarly in other animals. Leucism is a recessive condition. In sugar gliders it does not seem to have any negative effects on the animals health. Leucism can be reliably bred for, and is clearly a recessive gene just like albino. We also have albino sugar gliders, and unlike other species of animals, a leucistic and an albino together actually make a normal colored glider.

So... i disagree that it is a "lack" of color in the genetics, if that was the case, breeding an albino with a leucistic should produce white babies... when the offspring have the normal coloring that both parents lack. The conclusing is that leucistic and albino coloring behave exactly the same genetically, but they are on different alleles.

The website that documents the genetics of the sugar gliders is http://www.thepetglider.com/index/online-pedigree-program.html Adonis is a leucistic glider, here is his pedigree: http://www.thepetglider.com/pedigree/modules/animal/pedigree.php?pedid=4662 And Chloe is an albino, here is her pedigree: http://www.thepetglider.com/pedigree/modules/animal/pedigree.php?pedid=4867

Then, to prove that they are both genes that work on different alleles, this is the pedigree for Domingo, whose mother was a leucistic and father was an albino, and he was the standard color. If neither of the parents had the capability to pass that on, they would not have produced him with normal coloring: http://www.thepetglider.com/pedigree/modules/animal/pedigree.php?pedid=7201

Just wanted to share what I do know about genetics.

Leucism and Albinism are different

Leucism is a defect in the cell itself with the result of a lowered or lack of pigment. Pigment (melonin) still exists in the body for example the eyes of a Leucistic animal will be "normal colored" black or blue etc. In an Albino the body lacks the ability to produce melonin and the result is a white animal but with pink/red eyes, which is simply a result of the blood vessels showing through. Leucism and Albinism are VERY different, they can simply look similar. — Preceding unsigned comment added by 132.3.37.81 (talk) 15:35, 27 June 2013 (UTC)

Leucism is not always a recessive trait

Regarding my recent edit. The page already used dominant white as a reference. I double-checked that dominant white is a form of leucism: "In horses, twelve mutations that cause leucistic white or white-spotted phenotypes such as sabino spotting or dominant white have been described so far" (Cieslak, Michael, et al. "Colours of domestication." Biological Reviews 86.4 (2011): 885-899.)

English spotting in rabbits would be another example of a form of leucism that is not recessive. I'm certainly not disputing that leucism often is recessive (eg Vienna white and dutch marking in rabbits). I could probably find some examples in mice that would be more notable.

I've not tried to clarify that strictly speaking the various alleles are only dominant or recessive relative to the wild type alleles. Finally, note that IMO dominance (genetics) has a better description of dominant/recessive than the deleted link to recessive allele. Please bear that in mind if you think dominant and recessive need wikifying.

TuxLibNit (talk) 01:01, 23 December 2013 (UTC)

Isabellinism

in the article Isabelline_(colour)#In_animals it says,

The genetic pigmentation disorder isabellinism seen in birds is derived from the colour word and is a form of leucism caused by a uniform reduction in the production and expression of melanin resulting in areas of plumage on the back of the bird, normally black, being strongly faded, or isabelline, in appearance.

(my bolding)

besides being awkwardly worded, i'm wondering if there should be mention of this on this article, and what exactly is the difference between isabellinism and leucism.

it looks like leucism is a reduced amount of all pigmentation, and isabellinism is just a reduction in melanin of the plumage on their backs?

or is it just more noticeable on their backs, as maybe the birds with this condition normally have white/light coloured undercarriages? ≈Sensorsweep (talk) 01:01, 24 October 2014 (UTC)

If one uses the definition of leucism in the wp article, then the identification of isabellinism as a form of leucism is highly suspect. Before linking the articles further, I suggest you try to find a source for the claim (that isabellinsim is a form of leucism) and if you succeed then also check it is using the same definition of leucism.

Regarding whether this is specific to the back I'm pretty sure the text is trying to say "areas that are normally black are lightened", "in these birds the back is normally black" and "that is why the back is lightened in these birds". So this is a general lightening of dark areas, not specific to the back.

– TuxLibNit (talk) 21:52, 26 October 2014 (UTC)

Following that up myself... The Isabelline_(colour)#In_animals section has two sources (by the same author) that should contain the leucism claim (Wingspan and Notornis) but I was only able to check Notornis. That article actually argues against referring to these pigment defects as leucism, "Some authors have used the term leucistic to describe birds with very pale or washed-out plumage ... we suggest that isabelline is a more appropriate term for birds with this 'faded' plumage.", and gives three cites for "some authors". The earliest of these is Sage (1962). "Albinism and melanism in birds". British birds (55): 201–225. which says on p. 204, "Individuals in which the normal pattern and colour of the plumage is discernable but very pale or washed out in appearance are said to be leucistic or dilute. ... Other synonymous terms for this condition are ghosting or schizochroism.". So I think it is safe to say these articles are not using the lack of chromatophore definition from the WP article. Having also noticed that the white lion depicted also does not meet the lack of chromatophore definition (its colour is attributed to a reduction in tyrosinase function), perhaps the leucism article itself is in need of a change. With that in mind, can anyone tell what the article is citing as the source for the lack of chromatophore definition, and in particular, on what basis does it consider it the only correct definition? It is not at all clear. Having fought through a few broken links, only one of the six explicit article references actually mentions leucism or leucistic and that's the OED.

– TuxLibNit (talk) 22:28, 29 October 2014 (UTC)