Pallids, buttercup : HOW??? WHY???

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Recio
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Pallids, buttercup : HOW??? WHY???

Post by Recio »

Hi, everybody;

Pallids IRN display a loss of melanine in the head of both males and females, and a lighter body colour in green and blue series. See here: http://home.wanadoo.nl/psittaculaworld/ ... aWorld.htm

Buttercups display also this loss of melanin in males but not in females, and it appears when the bird reaches sexual maturity. They also display a lighter body colour. We can conclude that this melanin block is regulated by sexual hormones.

Question: The melanin regulated by sexual hormones in buttercups is the same than the melanin lacking in pallids? Has anyone tried to test it?

Cheers

Recio
Fah
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Re: Pallids, buttercup : HOW??? WHY???

Post by Fah »

Well, a few key questions/issues pop up.

What do you term as buttercup as being? This is an old debunked name, and has been used extensively between two seperate mutations (combinations of as well) throughout the countries and regions.

Pallid-ino (in the green series birds) has been referred to as Buttercup.
Clearheaded has been referred to as Buttercup (quite commonly still).

Both pertain to the same sexual maturation issues to an extent that you described, so I am just trying to figure out which you are talking about.

The only reason I ask as the comparison between Buttercup in relation to the term Clearheaded, to the pallid mutation, seems like comparing apples to oranges.
Recio
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Re: Pallids, buttercup : HOW??? WHY???

Post by Recio »

Question open
Last edited by Recio on Sat Oct 17, 2009 5:48 am, edited 2 times in total.
Fah
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Re: Pallids, buttercup : HOW??? WHY???

Post by Fah »

The only reason I was curious about your terminology is due to the fact I wasnt expecting a person so heavily involved in genetics to be using such an outdated and often misused name that is, in essence, a opportunity for confusion on a forum where people from all over the world meet, all of which have various names. Focusing on the correct term academically recognised keeps those up and comming alert to what is actually being discussed (not to mentional sticking to what should be as time goes on, the more recognised term).

I had asumed like you said, hence the last sentence.

I should have put little numbered points next to the paragraphs as so... as this is what I had in my mind when I wrote it.

1) Pallid-ino (in the green series birds) has been referred to as Buttercup.
2) Clearheaded has been referred to as Buttercup (quite commonly still).

1) Both pertain to the same sexual maturation issues to an extent that you described, so I am just trying to figure out which you are talking about.

2) The only reason I ask as the comparison between Buttercup in relation to the term Clearheaded, to the pallid mutation, seems like comparing apples to oranges.


An example of broken paragraphs and not so well structured posts being a major downfall. I was attacking the first statement in one sentence, followed by the second statement.. which seemed perfectly clear at the time of writing lol, but not upon reading. :P

A simple drawn conclusion for similarity/dissimilarity between Apples and Oranges is a well discussed play on the validity of comparison, to which I also thought a smart cookie like yourself could draw on what I was saying.

These are two mutations that are both similar and dissimilar and I am trying to figure out why such a strong drawn comparison between these two specific mutations are being made? For the sake of discussion and curiosity and such a discussion could warrant the similarities and dissimilarities between a rather larger group within which the reduction of melanin in the head can draw on quite alot of talk (bronze fallows, cleartails).

It is not just the male in the Clearheaded line that experiences reduced melanin, the hen also has a diluted form, yet you are saying the hen is devoid of such a reduction of melanin. The only variation between the hen and the male is the head in such a regard no?

Could it be an idea to now follow on proper discussion, or is deriding questions/discussion the new learning 'slap in the face' we are to adopt?
Recio
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Re: Pallids, buttercup : HOW??? WHY???

Post by Recio »

Question always open
Recio
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Re: Pallids, buttercup : HOW??? WHY???

Post by Recio »

Hi everybody;

Let's analyse:

To study melanin mutations the best way is to begin by analysing the easiest mutation:
Complete inhibition of melanin synthesis: this is the lutino IRN which can be further divided, from a genetical point of view, in SL-ino (sex cromosomes) and NSL-ino (a locus in autosomal cromosomes). Each of these genetic possibilities has at least 2 alleles:
SL-ino/pallid
NSI-ino/bronze fallow

So here we have a simple model with enough variation to analyse the regulation of melanin synthesis in the IRN. I will not attack the NSI-ino/bronze fallow discussion because there are not enough pic available to conclude anything.

Other mutations adding complexity would not be a good candidate for initial approach.

As I stated above there is a surprising similarity between the adult male phenotypes of pallids and buttercups (clearhead fallows), at a point, that some brillant pallids can almost look like clearheads fallows, as has been recently pointed in the forum. On the other hand we have a very important dimorphisme between pallids and ch fallows in youngs and females. To me this point out that there is a regulation of melanin synthesis by sexual hormones... and we could make the hypothesis of the existence of two different melanins: hormonal dependant and hormonal not-dependant.

Hormonal independent melanin: this would be the melanin shown by pallids. It is an homogeneous layer of melanin througout the whole body but the head. In pallids the head is free of any melanin. This is a very light layer and this is the reason that pallids display very light colours, mainly in the blue series where no psitacine is present to "increase colouring". I thinck that pallid mutation prevents any synthesis of hormonal dependent melanin from birth. Data in this sense come also from the effects of pallid on opaline mutation: when looking at a combo of pallid-opaline (look at Jay's pic) we can see that pallid prevents opaline induced changes in head colouring (darkening) which are mediated by a hormonal mechanism.

Hormonal-dependant melanin: it is the melanin which disappears from males ch fallows when reaching sexual maturity, making them to look very much like pallids. This melanin layer dependent on sexual hormones is present throughout the whole body and head. Clearhead fallows mutation would be an increased sensitivity of melanin to the down regulation of sexual steroids.

So, in conclusion, by analogy with the two layers of psitacine, we could speak of a light melanin layer in body but not in the head (represented by the phenotype of blue pallid) and not regulated by hormones, and another layer throughout the whole body which expresion would be regulated by hormones. Depending on the amount of hormones and the degree of sensibility we could obtain different shades of greys. Probably this layer, regulated by hormones, is the layer which is afected in the dilute mutation, since dilution occurs in the whole body and head.

The experiment to support this hypothesis would be to try to "dilute a pallid" bird: if the hypothesis is right you would not be able to dilute a pallid.
Another experiment: to "dilute a clearhead fallow". If the hypothesis is right you would be able to dilute a clearhead male until reaching sexual maturity but afterwords the phenotype would be the same (or near) than a normal non diluted clearhead fallow.
Has anyone tried these experiments?

There are other possible considerations of this hypothesis: let's have a look at cinnamon males: in the green series they display a yellow head with green-cin body and in blue series they display a blue head and a light grey body .... I am just wondering if cinamon just affects only one of the two layers of melanin. It would be easier to explain the difference between the head and the body colours with the two layers of melanin hypothesis.

Please, let me know what you thinck

Greetings

Recio
Recio
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Re: Pallids, buttercup : HOW??? WHY???

Post by Recio »

Hi everybody,

I come back to the discussion of the two possible layers of melanine just to put them in relation to what has been called foreground and bacground melanine (I have just found this article). This discussion has been made by Clive Hesford so I will just paste and copy the most interesting part of his article:

"The main characteristics of eumelanin distribution are readily appreciated by visualising the Grey colour variety of the budgerigar, which has lost the ability to show either blue or yellow (and hence green) colouration. The black areas (known as the markings) have the same distribution as in the normal light green, or wild-type, and are caused by heavy melanin deposits in the cortex of the feathers. The lighter grey areas, which largely coincide with the body colour area (green in the wild-type), are caused by lighter deposits of melanin within the barbs of the feathers in the central region known as the medulla.

I have long called these two types of deposits foreground melanin and background melanin respectively, as an aid to describing the effects of budgerigar colour genes. This is not to imply that the two types are necessarily different either chemically or physically. The description background melanin derives from the fact that it is not directly visible (as grey) in most varieties and yet forms the essential background against which the blue colour (green when modified by the presence of yellow) produced by the action of the cloudy layer is displayed.

It has also been found that in some budgerigar colour varieties the relative concentrations of foreground and background melanin vary independently of each other, which further reinforces the decision to treat them as sub-elements which can be subject to separate genetic control. This would not be obvious in those species which do not carry prominent black markings"


You can find the whole article in: http://www.birdhobbyist.com/parrotcolour/elements.html

I hope you will appreciate

Recio
Recio
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Re: Pallids, buttercup : HOW??? WHY???

Post by Recio »

Hi Saud,

If I am right foreground and background melanin would be the histological basis of the 2 hypothetic layers of melanin, but I have seen nowhere a study of melanin granules distribution in the feathers of IRN.

Best regards

Recio
Recio
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Re: Pallids, buttercup : HOW??? WHY???

Post by Recio »

Hi everybody,

I have just found some more data in the sens of a double melanin layer. First I will copy and paste one part of the article of Terry Martin about interaction between genes in parrots:

There are rare examples of gene interaction in parrots, with the most celebrated being the gene interaction between mutant alleles of the dominant pied locus (P) and the recessive pied locus (r). These two partial leucistic colour morphs interact to produce a full leucistic colour morph when present together in the genotype. The phenotypic expression is significantly ‘greater’ than either allele in isolation. Or more precisely, the degree of residual function is dramatically reduced. To understand this perspective, consider that Pied colour morphs have reduced ability to deposit melanin (totally lost in an irregular pattern, but retained in other regions) in the plumage due to failure of melanocyte function in certain regions. Following on, a bird with the genotype P-rr is unable to deposit any melanin in any region of the plumage, which is a greater deviation from wildtype colouration and represents a greater loss of function. Whether one locus has a direct effect on the expression of the second, or whether the gene products of one interacts with the gene products of the second is unknown. Genetically, this interaction could be considered a case of dominant and recessive genes with cumulative effect.

You can find the whole article in : http://www.birdhobbyist.com/parrotcolou ... namon.html

The results about interaction between dominant and recessive pied mutations can be easierly explained if considering that each one acts only on one melanin layer, instead of thinking about gene interactions. To test the hypothesis we should check what would happen in a blue pallid bird when expressing the pied mutation:

1. If the two melanin layers hypothesis is true only one of the pieds type will be expressed, the other being 'hidden" by the lost of melanin in his specific layer. On the other hand there would not be a cumulative effect of the dominant and the recessive genes.

2. If the two layers hypothesis is wrong both mutations would be expressed by a blue pallid IRN and the cumulative effect, then, would be possible.

Has anyone tried this experience?

Recio
Recio
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Re: Pallids, buttercup : HOW??? WHY???

Post by Recio »

Hi,
I have found some pics of recessive and dominant pieds which could contribute to the 2 layers of melanin hypothesis:
1.Recessive pieds: piedness affects the whole bird, head, body, wings,... look here: http://www.piedringnecksusa.com/
2.Dominant pieds: piedness does not affect the head, which is darker (does not loose any melanin) ... look here: http://www.mcw-indianringnecks.com.au/A ... tPied.html. Unfortunately these are the only pics I have found of dominant pieds. Can anyone post some more pics?

Dominant pied mutation would act on the hormonal independent melanin layer, not affecting the head.

Recessive pied mutation would act on the hormonal depending melanin, thus, affecting the whole bird. In this sense it should be said that these are called ADM pieds (antidimorphic pieds) because males do not express the ringneck (another hormonal depending feature), they look like the females. To know further about ADM pieds look here: http://www.sunbird1.co.za/new_page_8.htm (make right click and select everything to visualize).

Waiting for pics and comments

Recio
Recio
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Re: Pallids, buttercup : HOW??? WHY???

Post by Recio »

Hi Saud,

I know nothing about budgies. Playing with IRN genetics is enough for me ... :lol: :lol:
Anyway to say that they inherit dominant or recessive respective to the pied mutation, it does not mean that there are just 2 types of pied: in budgies there are at least 3 different pied loci and each one can hold several different alleles. In IRN there are at least 7 types of pieds (one inherits dominant and the others recessive). Whether they are different alleles (variations) of the same gen or different mutations in different genes needs further study.

Respective to dominant pieds: it seems that it is not clear whether the head is affected or not by piedness. If you look here you will find birds shown as dominant pieds with piednnes in the head:
http://home.scarlet.be/~av025776/Fotos% ... s%209.html ..... dominant pieds?
http://home.wanadoo.nl/psittaculaworld/ ... rameri.htm ..... similar pied marks in rec and dom pieds?

Have you notice that there are not any pic of pallid pieds nor clearhead fallows pieds neither clearhead pieds? I have been looking for them in the web for more than 6 hours and I have not found a single pic of them :evil: . Nevertheless I am sure that breeders have tried to get them. Since the most available pieds are recessive we could think that recessive pieds and "clearhead" mutations can not be expressed at the same time. I have made a new post looking for these pics. Let's wait and see if somebody has a pic of them

The only pic I have found comes from Jay (in a forum in Philippines) but it is not clear if it is a pallid pied or clearhead pied, and in this case it seems to be presented as a dominant pied:
http://philippinepetfinder.com/forum/vi ... a027fb0f77
And here is the link to translate from tagalot: http://translate.google.com/translate_t ... 7Cfr#tl|fr|
The same bird is presented as a blue pallid recesive pied in:
http://www.indianringneck.net/PetPics.html ..... respective to the white tail: it is piedness or is a cleartail?
http://www.indianringneck.net/MutationPics.html
Jay, could you highlight us about the exact mutation in the pic?

If recessive piedness can not be expressed in pallids but dominant piedness can be expressed, it adds consistency to the hypothesis of the 2 melanin layers. :roll:

Advise for fanciers: :idea: if this is true, to introduce piedness in "clearhead" mutations (pallids, clearhead fallow, cleartail) you should work with dominant pieds and avoid recessive ones.

Regards

Recio
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