I have been wondering this for a while, but is there any difference between amelanism and albinism? Or are they the same thing? I would think they are the same since amelanism indicates a lack of melanin just like albinism, but maybe there is some difference that I just haven’t noticed. And if there isn’t a difference, why do we use two different terms within the reptile community?
And just to tag someone that I have a feeling will know the answer @t_h_wyman I summon you.
But an albino animal isn’t one with a lack of all pigments, just melanin. A leucistic animal would be one that is all white, and I have (rarely) seen some leucistic rat snakes with pink eyes. In order for an animal to be all white, it would have to lack more than just melanin. It would have to lack the pigments that makes it have yellow and red too. And whatever other color it might have.
As I understand it and I could be wrong. Albino is from Latin and means “white” so has been used for Albino humans, etc. It’s usually applied to most animals that lacking melanin would be white but doesn’t really take into account multiple different pigments and the genetics involved, it’s just a white animal or human. Amelanism is a way more precise term denoting the exact pigment that is turned off. Technically, there are a ton of, say corn snake morphs, for example, that would all qualify for the term Albino but there are many different genes involved, which is why it’s not a term generally used nowadays.
While I will follow the generally used terms in different species, I do appreciate the corn snake market where a bigger push is made to be precise than some other species.
Sorry to be a bit late to the party, I do not tend to jump on here on the weekends.
@elementalexotics hit the nail on the head though. Albino/Amel are just to different ways to say the same thing. Historically Albino was used to describe the red-eyed/white phenotype that was most commonly known from mammals which only have melanin. As time (and science) progressed it became obvious that some animals have more pigments than just melanin and when you take melanin out of those animals they still have some kind of colour left over.
Depending on just how anal-retentive of a person you are dealing with, some people will insist that animals that are phenotypically red-eyed/white are “Albino” while animals that are phenotypically red-eyed/white+red or +yellow are “Amel” even though the basis of the morph is the exact same gene.
So it is as I was thinking. Same genes, just different terms. I will probably stick to using albino since more people know the term, and it is the one I started out using. Thanks for confirming what @elementalexotics said (and thank you elemental for chiming in too).
Amel is designated by the exact pigment that is turned off, specifically Tyrosinase.
Let’s take Burmese Pythons. There’s Albino and Caramel. Albino in Burmese is Tyrosinase negative, which makes it technically Amel but it’s still a type of albinism. Caramel is Tyrosinase positive. It’s still a type of albinism.
In Retics, the most common Albino (purple, lavender, white, Mochino, etc) that reside on the same loci are Tyrosinase positive albinism.
Amel in Retics (and the other genes compatible on that loci) is Tyrosinase negative which is why Amels have red pupils versus a lavender which has black because there’s still the melanin producing enzyme Tyrosinase. Keep in mind, breeders name animals genes without genetically testing them. Amel in Retics isn’t named because of the color of the animal but because the original Amel was named Amelia. Any breeder can name a new morph whatever they want, even if it’s not ‘genetically’ true.
I’ve attached a side by side comparison of a Tyrosinase positive Lavender Albino Retic and a Tyrosinase negative Amel Albino Retic.
Yep, same kind of situation. We see it in some boa, retic and burm morphs as well
Amel is shorthand for amelanistic. a- is a prefix of negation from the Greek usage a- or an- for “not” and melanistic is a derivative on melanin that comes from the Greek term melanos, meaning “dark,” Thus, literally translated as “not dark”, or, more properly, not carrying the dark pigment melanin.
Tyrosinase is not a pigment, it is an enzyme that processes tyrosine. The processing of tyrosine is a necessary critical step in the production of melanin. When tyrosinase is absent, this critical step cannot occur and so the pigment is not produced.
Or they named her “Amelia” because it played of the already existing and long-established use of “Amel” being used in the hobby and the story was corrupted with time…
As I noted above:
How long is a piece of string?
There is no cut or dry answer to that.
In terms of genetics, there is only one type of albinism; Tyrosinase-negative (T-neg) amelanism. Anything that is not T-neg is more properly classified as hypomelanism (the “hypo-” prefix deriving from the Greek for under/below) because they are producing melanin, it is just displayed at less than (read: below) normal levels.
In the absence of genotype, anything that gives the phenotype of red-eye, white (or red-eye, white/yellow, red-eye, white/orange, red-eye, white/red in organisms that have pigments in addition to melanin) is typically considered albinism. This is why there are multiple “albinos” in boas and Burms and retics and humans. Logically, we know that only one of them can be the actual real Albino, but unless/until a genetic level interrogation is done, we are left with nothing but guesswork
I appreciate the response and enjoy chatting genetics.
To my understanding, and the understanding of the history of Amel Retic history, Amelia was named as such not because of her color. She was also named as such prior to proving out the gene as hereditary.
Where we disagree is about how many types of Albinism there is. While I do agree that Amel/T negative is the most traditional form of Albinism and the one we immediately think about when we hear that word: picturing a red eyed animal with white/yellow skin. Recent studies show that in humans alone there are 7 types of Albinism, both T + and T -. The enzyme is defective so it does help create some melanin but it’s incomplete, thus creating a type of Albinism-one could say it’s incomplete Albinism. I think that the same can be said for animals (with various number of Albinism in different species)
I am very interested in this conversation and do appreciate the responses.