Blue, turquoise and acqua, WHY??? HOW???

[Recio]

Hi everybody;

Blue, turquoise and acqua are supossed to be different alleles of the same locus, presenting an order of dominance as follows: acqua > turquoise > blue. It means that all of them will modifie the synthesis of psytacines (yellow and red colour) but each one in a different manner:

1 . Blue allele does not allow any psytacine sinthesis and thus the bird appears blue

2 . Acqua allele also does not allow any psytacine synthesis and the bird appear light blue. I have read in mutavi pages that lighting occurs throug a decrease of 50% in the production of melanin. WHY or HOW does it happen? Are there any coupled genes controlling both psytacine and melanin production? How can the same mutation act on 2 different metabolic pathways leading to different pigments? Is there any simple explanation?

3 . Turquoise allele allows a partial psitacine production but this production is not equal throughout the whole bird: it is much more evident on the head and wings. Far more the degree of expresion ranges from 20% to 80% depending on strains/individuals. Again the question is WHY and HOW an allele of a gen coding for psytacine synthesis can act also on distribution of the pigment.

So there is a triallelic system of the gen coding for psytacine synthesis which would be able to act also on melanin pathways (see acqua) and on pigment distribution (see turquoise) ...

Can anybody further develop?

Cheers

Recio

PS: Temptation to use colours was too big

[Recio]

I have read in mutavi pages that lighting occurs throug a decrease of 50% in the production of melanin

Recio
Are u sure that in the above statement Mutavi mentions melanin and not psittacine?
It would make more sense to me if the gene was reducing the production of psittacine by 50% so that the bird appears light green due to lower production of the yellow pigment?

Am I making any sense?

Hi Saud,

You are right and I was wrong . The article was about a 50% reduction in psittacine and thus, as you say, it is easier to understand this mutation.

Thank you for the correction (and this is the second time )

Cheers

Recio

[Recio]

Hi Recio,
I am a keen student of genetics and still learning from experienced breeders like yourself. If I see anything that is contrary to my understanding I point it out to clarify my own concepts.

Hi Saud;

I am not an experienced breeder. I have been breeding IRN for just 5 years and I only have 8 reproductive pairs. This is my hobby. I am interested in genetics, like you, but I do not have either your theoretical background or the experience.... so your knowledge and the experience of many others are always welcome

To me the effect of the turquoise gene seems analogus to the pied gene.

The pied gene effects the production of melanin in an apparently random pattern.
The turquoise gene does the same for Psittacine.

Let's discuss about this; are you ready for brain storming?

1 . In the pied IRN there is a lost of melanin in a random pattern and apparently there are at least 4 or 5 different mutations which could produce pied IRN (one autosomal dominant and the others autosomal recesive). The random pattern in pieds depends on a random loss of melanin due to an altered migration of cells originating in the neural crest during embryogenesis. These cells are the precursors of melanocytes, which will produce melanin. This is the accepted theory (if I am not wrong) ... but I have a problem to understand this: since the colouring of a single feather depends on the presence of melanocytes in its folicule while it is growing up, we should expect feathers without melanin (just with psitacine) or with different degrees of melanin, depending on the concentration of melanocytes in the folicule, but the same in each feather. When you look at the feathers of pied IRN they do not seem homogenously coloured. We could say that every single feather is pied, that is, every single feather has a random pattern within itself (if I am not wrong in my perceptions). I would like to know what other breeders feel.

2 . About turquoise: turquoise distribution is not really random but it is concentrated on some body regions (mainly head and wings) having a great variable expressivity depending on strains or birds. When looking to other psitacula you will also find an increase in psitacines in these areas (Alexandrine parakeet, plumheaded parakeets, blossomheaded parakeet, Seychelles parakeet, ...). When looking to IRN psitacine distribution in melanin free birds as lutinos or pallids/pallidinos it seems that there is far more psitacine in the heads and wings that in other parts of their body, even without the turquoise mutation. What all this means?

To me it seems like if there were two layers of psitacine in psitacula birds: a whole body layer and another one mainly restricted to head and wings.
a) Turquoise mutation would act through elimination of the whole body layer, thus becoming more apparent the "restricted layer" and resulting in ... turquoise patched bird. The restricted psitacine layer becomes completely apparent after eliminating melanin: this is the creamino.
b) Acqua mutation would act through elimination of the psitacine "restricted area" resulting in a solid turquoise colouring by the addition of melanin + homogenous psitacine layer. If you remove the remaining melanin you get the aquaino (homogeneous light yellow).
c) Blue mutation would be able to eliminate both layers leading to blue colouring without any psitacine. After removing melanin you can get the albino.

Of course this is just a hypothesis, but if it was true creamino would just display the restricted psitacine layer and aquaino would give us the homogeneous layer.

Let me know what you think. Discussion open to everybody.

Cheers

Recio

[Recio]

Hi Saud,

1 . About expresion of psitacine within one feather in turquoise birds: I think that the best way to verify is to look at feathers of creamino birds to avoid interactions with melanin. As far as I know the psitacine pigment is not present in patches within one feather.

2. About genetics of the hypothetical double layer of psitacine: the fact of turquoise, acqua and blue as being alleles of the same gen does not disturb me that much. There are many possibilities of regulation:
a) The gen coding for psitacine could in fact be a master gen regulating two others gens (one regulating the homogeneous layer and the other regulating the "restricted" layer). It does not mean that aqua or turquoise mutations depend on mutation of the regulated genes, but that the master gen would regulate one and/or the other depending of which allele is present. With this possibility I join your above statement.
b) Another possibility would be that the threshold of activation of metabolic pathways for one or another layer could be different ...

In fact genetics provide the theoretical basis for understanding reality.

Let's develop further the hypothesis of the double psitacine layer (trying to approach the reality):

1 . About the homogeneous layer: it should have been the first to appear, providing the birds of a great selectiv advantage as they would appear green. This should be a very stable layer since it would be related to the chances of survival of birds in the wild. This layer would be present throughout the different species of parrots. I think this layer is very stable, I mean not "prone" to mutations.

2 . About the restricted layer: to me this layer would be more recent and has allowed different psitacula species to evolve. This layer would not be as stable as the above one and more prone to mutations: reasons:

a) Variation in surface area: turquoise expresion is very variable (20-80%) between strains or birds. In fact I think that instead of defining turquoise by its action (patched psitacine in the restristed areas) it should be defined by its "non action": never colouring flight feathers of wings and tail. In this sens it is to remark that lutino flight feathers are light yellow, exactly like acquaino flight feathers. From a mathematical point of view we could say:
lutino phenotype = creamino phenotype + aquaino phenotype.

b) Variation in intensity of colouring and in psitacine type:
b.1 : Males reaching maturity show a brighter green colouring in the restricted areas (head and wings), or a deeper yellow in lutinos, when compared to youngs or females. If the hypothesis is true we should not find these features in aqua or aquaino males. Does anybody have pictures of these birds to compare?
b.2 : Males reaching maturity display a black-red ring. Red colouring depends on psitacine production, and thus, we can asume that it is controlled by the same system than the restricted area. Far more, intensity of the restricted area (as stated above) and ring developement are both depending on sexual hormones. So, birds not displaying the restricted area (aqua and aquaino) should not show any red colour in the ring, and birds not displaying the homogeneous layer (turquoise and creamino) should display the red coloured ring. I have just look in http://home.wanadoo.nl/psittaculaworld/ ... rameri.htm and ... IT IS TRUE. THEORY WORKS !!!!

So, we could conclude saying that the homogeneous layer would be quite stable throughout the time and the species (in fact the evolution) and that the "restricted" layer would be more "prone" to mutations, facilitating speciation, and would be regulated by sexual hormones.

: If trying to obtain a red mutation breeders should work on turquoise mutation.

What do you think about the two layer hypothesis? Could it become a theory? Waiting for comments and data for and against the idea.

Cheers

Recio

[Recio]

Hi Saud,

How is processing going on?

There are two points about which I have been thinking:

1 . The red colour of the ring in lutinos is far more marked than in creamino. So, to say that lutino colouring is just the addition of creamino and acqua seems too simplistic to me. One possibility would be that red psittacines were derived from yellow psittacines, and thus, the increase in yellow psittacine disponibility in the follicule of lutino IRN (with respect to the creamino IRN) would increase the synthesis of the red psittacine. In this sens we should remark that, in other species of parrots, red mutations occur always in yellow patched areas, meaning that at least one part of the mechanisms involved in such a synthesis is common to both psittacines. Unfortunately the metabolic pathway of psittacines synthesis (there are at least 5 different psittacines) is unknown.

2 . There is a particular finding in adult males head which is referred as brillance and which is maximal around the beak. This brillance is present in lutino and creamino birds but not in acquaino. To me it would be an additional characteristic of the "restricted" layer.

Greetings

Recio

[Recio]

Hi Saud,

If I had the chance to overview a great number of wild IRN I would look to some characteristics:

1 . Looking for melanin mutations: as far as I know there are not melanistic IRN. The mutations with increased colouring or darkness (grey, dark factor or violet) depend on feather structure and not on increase melanin. In green series birds (grey green, SF or DF green, violet green) the most important changes appear on the flying wing and tail feathers, so I would look for birds with dark-black tails, dark wings and dark nails. You would be a lucky (and fortunate) man if you have the chance to detect the first melanistic IRN (for breeding black IRN and increase colouring through combination with other mutations).
I would also look for green IRN with red or plum colour eyes and for any albino, creamino or lutino with red or rose patches, or a marked red ring.

2 . I would also look for piedness, that is I would buy IRN with "not pure colouring", displaying spots of different colours, providing they are not ill. There are many different types of piedness, so why not another one? Heterozygotic recesive pieds differ of wild animals in their cry, so I would also look for birds with a different cry.

3 . I will also pay attention at animals showing a marked difference in deep of colouring between the head and the rest of the body, since many mutations play at this level: pallid, fallows, cinamon, opaline, ...

4 . Finally I would also look for quality of feathers, long tails, good size and weight, ... and iridiscence.

Brillance means something like brightness, shininess, iridiscence, .... My first language is not english so I am affraid I can not do better. Can anybody help us?

Greetings

Recio