Biallelic expresion

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Recio
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Biallelic expresion

Post by Recio »

Hi everybody,

I have noticed that there are a lot of wrong ideas in basic concepts as what a dominant or a recessif mutation are. Ex: when people says that Green is dominant respective to Blue they think that somehow Green does not allow Blue to be expressed, or that Green "down regulates" Blue expression. Similar for Parblue respective to Blue. This is wrong. Every allele present in a locus is expressed, that is, each allele codes for its specific protein which allows to get the final effect. What we can see is the result of the addition of the effects of each allele. Or, if you prefere, we can say that every allele is codominant. Let's analyse some exemples at the Blue locus:

1. Green/Blue: this is a bird with an allele coding for psittacin together with a Blue allele. Blue allele is the null mutation meaning that it is not translated or that the final protein is not functional, so that not psittacin is produced. We have a green bird because one single Green allele is able to produce enough psittacin to saturate the system (the metabolic system and/or our visual capacity to detect increased concentrations of pigments). Let's say that the green allele produces 100% psittacin and the Blue allele produces 0%. The result is a green bird.

2. Wild type. This bird is a genotypic GreeenGreen for the Blue locus. Each allele produces 100% psittacin. Both alleles are able to produce 200% psittacin, but since the system is saturated at 100%, what we see is the same green colour than a Green/Blue (or GreenBlue).

3. TurquoiseBlue: let's say that the Turquoise allele produces 35% psittacin. So a TurquoiseBlue will show 35% + 0% = 35% psittacin = TurquoiseBlue phenotype.

4. TurquoiseTurquoise (homozygous Turquoise): it will produce 35% + 35% = 70% psittacin (here I am considering a lineal correlation which is only an aproximation to saturable phenomena)

5. Green/Turquoise (or GreenTurquoise): it will produce 100% + 35 %= 135 % psittacin. It will look like a green bird since the system is already saturated at 100%.

You can do similar reasoning for Indigo, considering a lower psittacin expression for each Indigo allele (let's say 15%).

This reasoning points to some "strange things":
1. If we ever have an heterozygous parblue (ParblueBlue) showing 80% of psittacin we should expect the homozygous phorm (ParblueParblue) to own 160% of psittacin and apear as a visual Green bird. If this Parblue exists we could also say that some of our supossed Green/Parblue birds producing 100% Parblue offspring when mated to a Blue bird, are in fact, homozygous Parblues.
2. Any bird owing an Emerald gene should show the specific Emerald fluorescence, independently that Emerald is a Blue allele or a different mutation. This has been shown in Turquoise Emerald combos and it should also be true for a Green Emerald (or Green/Emerald depending on hypothesis) ... but, as far as I know, nobody has made this study.

We should think in terms of two alleles expression, which is the norm, and the final phenotype as the result of the expression of both alleles and their possible interactions at the effector level (Ex Turquoise Emerald combo). An allele will likely produce the same protein than the "wild" allele but at a different concentration. Less frequently it will produce an sligthly different molecule.

This is valid not only for the Blue-Parblue system but for any mutation.

Regards

Recio
Mikesringnecks
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Re: Biallelic expresion

Post by Mikesringnecks »

Hi Recio
Given the foregoing, which I found to be both a necessary and excellent explanation, how do we explain the EmeraldTurquoise combo. For the life of me, I could never see patchiness in the combo at any stage of development.
I do only have the one TurquoiseEmerald bird. She is a cleartail and I have owned her from about 5 months of age. Usually, in a TurquoiseBlue Cleartail, the underside is extremely and very obviously patchy. She always had a plain yellow underside, albeit a different yellow hue than that exhibited by either a TurquoiseBlue or an EmeraldBlue Cleartail.
Kind regards
Mike
Recio
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Re: Biallelic expresion

Post by Recio »

Hi Mike,

I wrote: "We should think in terms of two alleles expression, which is the norm, and the final phenotype as the result of the expression of both alleles and their possible interactions at the effector level (Ex Turquoise Emerald combo). An allele will likely produce the same protein than the "wild" allele but at a different concentration. Less frequently it will produce an sligthly different molecule".

The Emerald gene expression is very different of the expression of the other patched parblues (its distribution, its regulation, its fluorescence, its iridescence ...) and this is the reason that 2 years ago I was considering the hypothesis of Emerald as a structural mutation. Today we have data showing that Emerald is not a structural mutation but a mutation acting on psittacin production:

1. As you say the combo Turquoise and Emerald is not just the addition of both phenotypes. It means that the expression of both of them act on similar metabolic pathways, very likely owing both a common precursor or similar regulatory enzymes, so that each one modifies the expression of the other, and the final result is not the simple addition of both phenotypes.

2. We know that the expression of psittacines is down regulated by the presence of melanocytes, so that the Dom Pied mutation (lack of melanocytes at the feather follicle), is able to increase psittacin production, and the patched areas in green series Dom Pieds appear with a deeper yellow. A similar regulation has been shown for Emerald, so that the combo Emerald Dom Pied is far more fluorescent than any of them.

These two findings point to Emerald as a psittacin rather than a structural mutation.

Whether Emerald is just an allele of Blue (it would be heteroallelic respective to the other homoallelic patched alleles), the result of alternative splicing (see here: http://www.bioscience-explained.org/ENv ... iceeng.pdf. I am sure you will enjoy this article), a part of a "big blue complex" or a highly linked gene, remains unknown. My idea is that it is a highly linked gene because its high number of differences respective to the patched parblues and its unique fluorescence suggesting that it is a different molecule. As I wrote, mutations usually act on the final amount of a specific molecule. If the final molecule is different we should think that we are dealing with another gene, but this is not always the case. Time will tell us but, till now, any one of these models fit with present results. The important thing is that we know far more about parblues and about genetics now than 5 years ago.

Regards

Recio
Mikesringnecks
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Re: Biallelic expresion

Post by Mikesringnecks »

Hi Recio
Thanks very much. As usual that detailed level of explanation was brilliant. As you suggest, I will doubtless much enjoy the reference.
Kind regards
Mike
Johan S
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Re: Biallelic expresion

Post by Johan S »

Recio wrote:Hi everybody,

I have noticed that there are a lot of wrong ideas in basic concepts as what a dominant or a recessif mutation are. Ex: when people says that Green is dominant respective to Blue they think that somehow Green does not allow Blue to be expressed, or that Green "down regulates" Blue expression. Similar for Parblue respective to Blue. This is wrong. Every allele present in a locus is expressed, that is, each allele codes for its specific protein which allows to get the final effect. What we can see is the result of the addition of the effects of each allele.
Amen! I have gotten to the point that I have distanced myself from wildtype > parblue > blue type of mutation discussions simply because most people proposing alternate points of view on dominant/recessive behaviour simply doesn't seem to grasp the above. And somehow they get really defensive when trying to help them.
Mikesringnecks wrote:Hi Recio
Given the foregoing, which I found to be both a necessary and excellent explanation, how do we explain the EmeraldTurquoise combo. For the life of me, I could never see patchiness in the combo at any stage of development.
Mike, please allow me to be the "fly in the ointment". I have always wondered about how "smooth" the colour distribution of an EmeraldTurquoise combo would be. Myself, I've had some doubts about the smooth expression that has been described by most breeders, simply because of the opening statement above of Recio, and how it doesn't make complete sense to me that two different psittacins are produced, yet they interact in this strange way to smooth out. So, with much anticipation I looked forward to my visit to Deon in December 2014, where I would see this combination in real life for an up close inspection. Much to my surprise, and Deon's, when we looked at the EmeraldTurquoise / Opaline cocks (15 months old at the time), it was immediately clear that the wing coverts were not what I would describe "smooth". The fluorescent psittacin was visible and different to the smooth appearance of the rest of the bird. And this from 2m away. What Recio would refer to as non-fluorescent patched psittican, like for example on the chest region, now that was very smooth, and neither turquoise-like or emerald-like, but rather the smooth combination that breeders and owners have reported. I am dead curious about a UV analysis of these EmeraldTurquoise birds, and the Green Emerald or Green / Emerald as well.

So a question to you: Is your EmeraldTurquoise a male/female? And another: Are you 100% sure that there is absolutely no "golden-ish" green tone to the fluorescent patched psittacin region (wing coverts)?
Recio
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Re: Biallelic expresion

Post by Recio »

Hi Johan,

Deon owns a "multirevolving" uv ligth with several different wavelengths to study birds fluorescence and he has shown us several high quality pics in the past. I am sure he has already look at his Turquoise Emerald combos under uv. Maybe he could contribute with his observations.

Mike has posted several pics of his birds under normal lighting in this forum and in FB. I know he is trying to get the uv lamp for better understanding fluorescence. Pics of uv fluorescence have been taken by exposing the birds to a black light with a wide longwave spectrum for a better image, but this type of ligth is not the best to look for specific differences between fluorescent psittacins. I could never get Emerald birds for a direct study (just some feathers) but under specific 395 nm uv ligth, in wild type and SL-Ino birds, I could detect a different yellow-green golden fluorescence between the wing patches and the head (the head fluorescence was greener and the wing patches were more golden like).

Regards


Recio
Molossus2
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Re: Biallelic expresion

Post by Molossus2 »

Recio
I have always understood the turquoise to be a different form of blue for want of a better description,,and not a combination of blue an other. Therefore blue is not needed for turq to express itself in sf ie..heterozygotically...Hence a green/turq to like paired produces this hetero turquoise.
My own observation of the emerald variation in its hetero form range from almost blue to a blend of greenbleu..so it follows that a lighter expressed hetero parblue will produce df homozygotes with possible low to medium % psittacins..this will cause a problem in visual identification of homozygote forms of parblue .. and test mating is necessary for ratification.
my own questions to you:
1 is it possible that perhaps indigo is a result of selective breeding of low % psittacins (lighter bluer birds)of the turq mutation?
2 Since parblue is a mutation originating from wild type green and the mutation did not rely on wildtype parents to influence its percentage of psittacins.. Will continued back mating to green increase the percentage of psittacins giving the mutation a greener look?
3 is the increase % psittacins the result of modification..
4 will the continued combining of parblue to blue result in a diminished blue form of the mutation ultimately? I always hear the claim of a mutation losing phenotypical traits ..eg opaline with not so 'dark' head and emerald looking bluer and bluer over generations..

your opinions here
Recio
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Re: Biallelic expresion

Post by Recio »

Molossus2 wrote:Recio
I have always understood the turquoise to be a different form of blue for want of a better description,,and not a combination of blue an other. Therefore blue is not needed for turq to express itself in sf ie..heterozygotically...Hence a green/turq to like paired produces this hetero turquoise.
My own observation of the emerald variation in its hetero form range from almost blue to a blend of greenbleu..so it follows that a lighter expressed hetero parblue will produce df homozygotes with possible low to medium % psittacins..this will cause a problem in visual identification of homozygote forms of parblue .. and test mating is necessary for ratification.
my own questions to you:
1 is it possible that perhaps indigo is a result of selective breeding of low % psittacins (lighter bluer birds)of the turq mutation?
2 Since parblue is a mutation originating from wild type green and the mutation did not rely on wildtype parents to influence its percentage of psittacins.. Will continued back mating to green increase the percentage of psittacins giving the mutation a greener look?
3 is the increase % psittacins the result of modification..
4 will the continued combining of parblue to blue result in a diminished blue form of the mutation ultimately? I always hear the claim of a mutation losing phenotypical traits ..eg opaline with not so 'dark' head and emerald looking bluer and bluer over generations..

your opinions here
Hi Lee,

Parblue terminology has been already deeply discussed in the FB forum. The explanations have been given by Mike, Madas and Willy. I have nothing to add.
About Emerald: we need to confirm if the homozygous Emerald shows more or less psittacin than the heterozygous Emerald. If it shows less psittacin it will point to a different mutation (a parblue allele of a second Blue locus) since its mechanism of action (partial inhibition) would be different than for patched parblues (partial activaction) suggesting an action on a different enzyme..
About evolution of Parblues: parblues are incomplete mutations and show a wide variation probably due to genetic, hormonal or environemental factors. Incomplete mutations (parblues, Dom Pied, ...) allow for the selection of specific markers through selection breeding. To me, Indigo is not a mutation but a morphotype (decrease psittacin production with white ring in IndigoBlue and pink-red ring in homozygous Indigo) which can be achieved through different alleles.
Is breeding to Blue or to Wild type able to decrease or increase recpectivelly the final amount of psittacins through the generations? I do not know but I guess the answer is NO, because otherwise those partial mutations which allow a better and quicker adaptation in Nature to changes in the environement would have disappear long ago, through continuous breeding of split birds to wild type.

Regards

Recio
madas
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Re: Biallelic expresion

Post by madas »

Recio wrote: To me, Indigo is not a mutation but a morphotype (...) which can be achieved through different alleles.
Hm, i thought different alleles are the cause for a mutation. :(

madas
Indian Ringneck Vic
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Re: Biallelic expresion

Post by Indian Ringneck Vic »

Recio wrote:white ring in IndigoBlue and pink-red ring in homozygous Indigo) which can be achieved through different alleles.
Is breeding to Blue or to Wild type able to decrease or increase recpectivelly the final amount of psittacins through the generations? I do not know but I guess the answer is NO, because other
Recio I know thiis outcome has been repeated though you need to note this is not always the case I have a family of Indigo that is represented by many cocks that been bred through homo pairing (indigo to indigo) some of these birds are in the fourth generation F4 and they do NOT have pink in the neckring they have increased psittacine though they do not increase their overlay area of psittacine.This past breeding season 4 birds were produced from 2 different pair that for the first time have advanced their overlay to almost their entire body these birds are F4 (indigo to indigo x 4 generations) though they are juveniles and to early to tell where it's going.The psittacine in this family is not green it is aqua.
Recio
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Re: Biallelic expresion

Post by Recio »

Hi Madas and Paul,

Let's go for the meaning of morphotypes. A morphotype is a phenotype that can be achieved through different mutations either of the same gene (different alleles) or of different genes.
Ex: for different genes: a yellow bird is a morphotype than a can be achieved through SL-Ino, NSL-Ino or DF Dom Pied. For the same gene: parblues.
Patched parblues morphotypes have been defined according to the quantity and distribution of yellow and red psittacins in heterozygous and homozygous birds, as follows (from less to more psittacin):
1. Saphire: no red ring in either ParblueBlue or Homozygous Parblue (to be proven).
2. Indigo: no red ring in ParblueBlue and ligth pink-red ring in homozygous Parblue.
3. Turquoise: red ring in both ParblueBlue and homozygous Parblue. In turquoise birds we could even make a difference between "ligth turquoise" (primary flying feathers without psittacin in TurquoiseBlue and with psittacin in homozygous Turquoise) and "heavy turquoise" (both TurquoiseBlue and homozygous Turquoise show psittacin in primary flying feathers).

When we define Saphire as a bird without a red ring in either heterozygous or homozygous phorm we are not meaning that this is due to just one specific allele (or one specific mutation). Ex: let's say that the red ring appears when the expression of psittacins is higher than 30%. In this situation any parblue allele producing less than 15% of psittacins will produce an Indigo bird. If we have 3 different alleles producing each 5%, 10% and 15% of psittacins, their homozygous phorms will produce 10%, 20% and 30% of psittacins but not red ring. These 3 different alleles would be classed as Indigo morphotype despite that they are 3 different mutations of the same gene. Similar reasoning for Indigo and Turquoise. Far more: we could even have heterozygous allele combinations of the same morphotype (ex: Saphire5%Saphire15% .... producing Saphire morphotype with 20% psittacins) and we could think that we are dealing with just one allele. This could explain Paul's results with Indigos.

About variability in patched parblue expression: every mutation shows a little variability in its expression. The variability is lower in heterozygous birds (ParblueBlue) with the null mutation (Blue) than in homozygous parblues since the null mutation does not allow any production of the final molecule (psittacin) and does not add variability. Ex: If we have a variability of 2% for a parblue allele producing 10% of psittacine, ,then the heterozygous ParblueBlue will show a viariability of 2% + 0% = 2%, and the homozygous ParblueParblue will show 2% + 2% = 4% variability. Again, the expression of each allele is independent and each allele adds also its variability to the final expression. If this is true .... why homozygous parblues appear more consistent in psittacin expression than their heterozygous counterparts? This is due to the logarythmic saturable relation between psittacin concentration and optical density (Yahoo forum).

There are also other factors which could lead us to think that there is a variable genetic expression:
1. Time dependency: the expression of patched psittacins increase with time up to the bird is fully mature. Birds should be compared at adulthood.
2. Sex dependency: there is a dependency on sex hormones. Since the level of sexual steroids is not the same in every bird we could find changes related to its sexual status.
3. Feather structure dependency: it has been shown that changes in feather structure are able to change the expression of psittacins. This has been done with Indigo birds respective to Violet. Once again this effect is not visible on birds with a high level of psittacins (Turquoise) but in young heterozygous Indigos, expressing a low level of psittacins which can be identified through uv studies. I have also found that the Grey mutation acts as incomplete dominant in Green series birds split for Blue and Cleartail, so that the DF Grey Green is far darker than the SF Grey Green. Since Grey acts as Dominant on Blue series it would mean that the change in feather structure also afects psittacin deposition on the feathers (I am waiting for feather moulting before uv studies). Similar studies of low psittacin expression (Indigo) in Dark and Deep would help in understanding the interaction between strcutural mutations and psittacin deposition.
4. Possibility of various alleles combinations able to produce each morphotype.
5. Possibility of apparent Wild birds being homozygous heavy Turquoise.
6. Existence of other patched parblues with a different regional distribution of psittacins (saddle parblues).
7. Possibility of existence of parblues acting through an inhibitory mechanism as in Budgies (probably a different locus) with homozygous birds owing less psittacin than the heterozygous ParblueBlue.

The question is: how could we study the variability of parblue expresion at the genetic level? We must study its expresion in birds of the same age and sex, showing the same feather structure, and owing the same parblue allele. We should pair an heterozygous ParblueBlue to an homozygous Blue. In this situation every Parblue offspring will be heterozygous for sure and then we can compare parblue expression between siblings. I have done it twice and at every time the offspring phenotype was the same. If we back breed the parblue offspring to the heterozygous parblue parent we will get the homozygous Parblue. Avoid pairing the heterozygous offspring from one pair to the heterozygous offspring of a different pair, to be sure that we are studying the same allele. This should be made with every different Heterozygous Parblue to obtain its homozygous expression.

@Paul: the green or aqua colour depends on the amount of psittacin produced (higher for green and lower for aqua) but it is always the same psittacin.

Regards

Recio
Indian Ringneck Vic
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Re: Biallelic expresion

Post by Indian Ringneck Vic »

Recio thankyou for explaination
Indian Ringneck Vic wrote:@Paul: the green or aqua colour depends on the amount of psittacin produced (higher for green and lower for aqua) but it is always the same psittacin.
this may explain the results I got when introducing Indigo into CHCT the pairs were hetro Indigo split CHCT to Visual CHCT x 3 pair in all prodigy produced the Indigo expressed in visual CHCT was reduced and in some cases vanish at first moult. The Indigo splits CHCT would seem to have their Indigo expression enhanced there were also a couple of birds that were normal (not visual for CHCT or Indigo) (11 chicks total).

This pairing was repeated last season and the results were surprising the majority of young were visual for CHCT with same result with regard to expression as year one only one split produced with Indigo visual no normals (9 chicks total )
Mikesringnecks
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Re: Biallelic expresion

Post by Mikesringnecks »

Hi Johan
I do like "flies in the ointment" it helps keep us all precise about what we report. In my case, with my TurquoiseEmerald Cleartail hen, when I was reporting a smooth expression of psitticins I must admit I was focused on her smooth pale yellow underside. That underside is very different from the patchy yellow underside I see on both young and mature TurquoiseBlue Cleartails.
I do have a few Green birds these day because I am trying to breed Green Opaline Cleartails and I just went out in the rain to have a look at their backs compared to the EmeraldTurquoise hen's back. From that casual observation, I would say the green hues are distinctly different but I could not detect that "patch" you normally see in young blue series turquoise bird in either the greens or the TurquoiseEmerald.
My TurquoiseEmerald hen is now a rising 3 year old. I can't photograph her with similar age Green Cleartail hens because they are just now hopefully pairing up with Opaline partners. However, I do have a rising 2 year old Green Cleartail cock that is still in the flock with her and most of the others.
When the weather improves, I can put him with her and a TurquoiseBlue Cleartail in my photo box and try to get side by side back shots if you think that will help.
Finally, I suspect that the wing patch we see in turquoise birds is primarily a feature of immature birds because I cannot easily detect it in my mature TurquoiseBlue Cleartails.
Kind regards
Mike
Recio
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Re: Biallelic expresion

Post by Recio »

Indian Ringneck Vic wrote:... the Indigo expressed in visual CHCT was reduced and in some cases vanish at first moult. The Indigo splits CHCT would seem to have their Indigo expression enhanced there were also a couple of birds that were normal (not visual for CHCT or Indigo) (11 chicks total).
Hi Paul,

Your results also point to a dependency of psittacin expression on the presence or not of another mutation (CTCH). Since we know that this is valid for Violet and Grey I guess that CTCH could be also acting at the structural level, producing secondary changes in pigment expression.

Regards

Recio
madas
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Re: Biallelic expresion

Post by madas »

Recio wrote: Since we know that this is valid for Violet and Grey I guess that CTCH could be also acting at the structural level, producing secondary changes in pigment expression.
But keep in mind that mostly (98%) the dominant mutations are changing the structur and the recessive mutations are responsible for changing chemical or hormonal processes.
So it is very unsual that CT is a structure altering mutation even if it is classified as fallow mutation. :( But there are still 2% remaining. :D

madas
Recio
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Re: Biallelic expresion

Post by Recio »

madas wrote: But keep in mind that mostly (98%) the dominant mutations are changing the structur and the recessive mutations are responsible for changing chemical or hormonal processes.
So it is very unsual that CT is a structure altering mutation even if it is classified as fallow mutation. :( But there are still 2% remaining. :D

madas
Hi Madas,

I have also read such thing but I do not remember where. Do you? Anyway I do not really agree because the number of dominant structural mutations is exactly the same that the number of recessive structural mutations. Do you grasp it?

Regards

Recio
Indian Ringneck Vic
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Re: Biallelic expresion

Post by Indian Ringneck Vic »

Recio thankyou for your kind comment on FB remember the detailed report I pm'd you a couple of weeks ago which you thanked me for. Though you were disappointed it was on a private format limiting you from public comment I took in your advice and decided to publish a shortened version on the public forum to enable you to move forward.

Ma Das confirmed my reluctance to go public by copying my publicized report on FB with a very spiteful smear in regard to the use of the terms Hetero & Homo I since published my reason with extracts from the Oxford dictionary then later I posted an extract from Terry Martin's book Page 216 under explanation of genetic terms Ma Das still refuses to explain my error.

This behavior has become endemic on these forums and I believe can only be viewed as counter productive.

If these public forums are to be of value snide behavior needs to be shunned and I urge the people that have the knowledge required to lead these forums to take an active role in correcting these people with a lesser standing to conduct their comments in a respectful way and refrain from using these forums for self gratification. Be aware we people on the lower tiers cannot do this effectively therefore the descision is yours, you either want us or you don't.

I do not mind providing input but I don't expect abuse.
Ring0Neck
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Re: Biallelic expresion

Post by Ring0Neck »

Hi Paul,

I do not remember seeing the FB post, so i did not see the error you are talking about about however here is a simple explanation of Hetero & Homo if it helps anyone.


In respect to Parblues; Turquoise, Indigo, Emerald

A Heterozygous Indigo can exist in 2 forms and look different:
1. Wildtype/Indigo
2. IndigoBlue (Heterozygous Indigo + Heterozygous Blue) One parent gave the young Indigo gene, the other a Blue gene.

A Homozygous Indigo = IndigoIndigo (df Indigo) both genes are Indigo, both parents gave the young 1 Indigo gene each.


Pairing IndigoBlue X IndigoBlue gives you IndigoBlues & Indigo (Hetero & Homo)
identifying visually a Homo V Hetero from above pair could be a challange and only by pairing the young to a blue resulting in 100% IndigoBlues young proves it Homo for Indigo. Once Homo bird is IDed, that should make IDing future Hetero & Homo easier.

one can only be sure they bred a Homozygous from the nest when both parents were proven homozygous birds.
just like in a dominant muatation: SF Violet X SF Violet you get Hetero Violet and Homo being DF Violet
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Recio
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Re: Biallelic expresion

Post by Recio »

Hi Paul,

My answer in the FB fórum was related to the violet subject. Like Ringo I could not see the Indigo post.

Heterozygous birds are those carrying two different alleles of the same gene: posible heterozygotes for Indigo from less to more psittacin:
IndigoBlue
SaphireIndigo (still to be fully identified)
TurquoiseIndigo
WildIndigo or Wild/Indigo

Here we are assuming that each morphotype is correlated with just one allele (still also to be proven). If we consider Emerald as an allele of Blue we could also speak of EmeraldIndigo. We do not know if both alleles (or mutations) together show more or less psittacin than the heterozygous IndigoBlue. It will depend on the partial activactory or inhibitory action of Emerald (still also to be proven).

The only Homozygous Indigo is, of course, IndigoIndigo.

About structural mutations: how many of them are Dominant and how many are recessive? The answer is exactly 50% each but the question is not correct: the mutations "are" not dominant or recessive but "behave" as dominant or recessive. We say that a mutation behaves as dominant when its allele is able to be fully expressed in its heterozygous phorm with the other allele. This other allele, not expressed, is call recessive respective to the expressed allele.
So for any structural mutation we have at least two different alleles coding for its protein: the mutated allele and the Wild allele. One of them behaves as dominant respective to the other, and the other one behaves as recessive, so, considering every structural mutation, we could say that there are as many Dominant alleles as recessive, or that we have 50% Dominant alleles and 50% recessive alleles.

Depending on the more frequently expressed allele (the most prevalent allele or Wild allele) the mutated gene will appear as recessive or as dominant, since the definition of dominancy is made respective to the wild allele. Our experience is that, for structural mutations, the Wild allele behaves as recessive (at 98% as Madas said) respective to the mutated allele. Is there any reason for this specificity? Why it does not seem to be random? Would be CHCT the only structural (if confirmed) recessive mutation? and what happens in other psittacula expressing a "white head" in wild birds? Do they express the equivalent of the mutated allele in IRN, and so for them the rule of structural mutation = dominant mutation keeps true?

Regards

Recio
Last edited by Recio on Mon Jun 22, 2015 5:36 am, edited 1 time in total.
Indian Ringneck Vic
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Re: Biallelic expresion

Post by Indian Ringneck Vic »

Thank you Ben And Recio
It seems I am guilty of a technical error my understanding was literal and not genetic based.As I am on a genetics forum I admit to being out of order.

My interest is a hobby where I breed birds I have no desire to delve into science therefore please acept my appology I can assure you it won't happen again.

My problem I have been unable to realise that there is two distinct aspects one is the genetic interest the other is the bird breeder as being demonstrated on FB currently the two sides should never mix.

Good luck.
Ring0Neck
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Location: Brisbane QLD AUS

Re: Biallelic expresion

Post by Ring0Neck »

Hi Paul.

We don't have to be all at the same level of genetic knowledge (and we aren't)
That's why we have Recioes, Johans and Madases around :)
I see Madas and Johan as our referees :D
The rest of us exploring, Recio leading ... holding the torch .

I too think there's a lot more to explore and even break some known rules, we can/should contest the rules of genetics known today
in 2 steps, at step 1 it should be explcitly said that it is a Hypothesis only (what if) (The Refs will ignore the rules and open to the idea, just like half time or time out )
1. Through Hypothesis a supposition or proposed explanation made on the basis of limited evidence as a starting point for further investigation
This is a great way to start to point out possible deviation from the norm, like Recio is looking at Emerald & Blue2.
Once we secure the strongest acceptable theory by referee's standards we move to step 2.
Step 2: Provide proof for or against the theory, through breeding results, inheritance etc.

I personally think you've done a great job with Indigos. I have not seen many breeders so commited & to be excited by exploring and discovering and that is a true breeder.
I'm an Explorer
10% luck, 20% skill, 15% concentrated power of will, 50% pleasure, 5% pain$ and a 100% reason ..I just gotta know
Johan S
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Location: Pretoria, South Africa

Re: Biallelic expresion

Post by Johan S »

Mikesringnecks wrote:Hi Johan
I do like "flies in the ointment" it helps keep us all precise about what we report. In my case, with my TurquoiseEmerald Cleartail hen, when I was reporting a smooth expression of psitticins I must admit I was focused on her smooth pale yellow underside. That underside is very different from the patchy yellow underside I see on both young and mature TurquoiseBlue Cleartails.
I do have a few Green birds these day because I am trying to breed Green Opaline Cleartails and I just went out in the rain to have a look at their backs compared to the EmeraldTurquoise hen's back. From that casual observation, I would say the green hues are distinctly different but I could not detect that "patch" you normally see in young blue series turquoise bird in either the greens or the TurquoiseEmerald.
My TurquoiseEmerald hen is now a rising 3 year old. I can't photograph her with similar age Green Cleartail hens because they are just now hopefully pairing up with Opaline partners. However, I do have a rising 2 year old Green Cleartail cock that is still in the flock with her and most of the others.
When the weather improves, I can put him with her and a TurquoiseBlue Cleartail in my photo box and try to get side by side back shots if you think that will help.
Finally, I suspect that the wing patch we see in turquoise birds is primarily a feature of immature birds because I cannot easily detect it in my mature TurquoiseBlue Cleartails.
Kind regards
Mike
Hi Mike, thanks for your response. I do fully agree with the very distinct phenotypic smooth/patched difference in their underside. For me the real curiosity appeared on the wing coverts. I wonder also if the difference in our observation regarding the patchiness might be because of the fact that we have studied different sexes, with you owning a hen and me looking at a /opaline cock? At this stage of the upcoming breeding season I do not want you to upset your birds with pictures, but the offer is very much appreciated. I hope that you manage to breed a TurquoiseEmerald cock for comparison with the hen.
Mikesringnecks
Posts: 218
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Re: Biallelic expresion

Post by Mikesringnecks »

Hi Johan
You could of course be correct about the sex making a difference and I also suspect that juvenile birds may be more patchy than matures. In addition, all mine are cleartails and I guess that too could impact on the outcome.
I could not get Green, TurquoiseBlue and TurquoiseEmerald Cleartails to show me their backs at the same time in the same light. However, the relatively obvious patchiness on the 2 year old TurquoiseBlue Cleartail cock as compared to a 3 year old TurquoiseEmerald Cleartail hen is relatively obvious both back and front in the attached photos.
Kind regards
Mike
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Johan S
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Location: Pretoria, South Africa

Re: Biallelic expresion

Post by Johan S »

Hi Mike, wonderful pictures, thank you! Here I suppose the use of a word 'smooth' is in the eye of the beholder. When considering the back view of your TurquoiseEmerald Cleartail hen, I would not call the psittacin phenotype on the wings to be 'smooth'. I can definitely see a difference in the colour of the different psittacins on her wing coverts, although the patched psittacin with her is not nearly as obvious as with the TurquoiseBlue. There has been some observations along the line of emerald smoothing out the turquoise phenotype to result in a smooth psittacin appearance, but for me this is not accurate. For me, I can see both genes at work here. And that is why I think the green / emerald (alt Emerald green) will be so interesting. We can clearly see a different colour green in the patched psittacin patch on the wing coverts. Will this transfer to the wildtype carrying a single emerald gene? Interesting times! :D
Recio
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Re: Biallelic expresion

Post by Recio »

:P
Mikesringnecks
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Joined: Sun Oct 06, 2013 11:45 pm

Re: Biallelic expresion

Post by Mikesringnecks »

Hi Johan
I accept that "smooth" is in the eye of the beholder. That is in part why I was trying to get a 3 way pic with the Green in play because the Green Cleartail is just about as "smooth" as the TurquoiseEmerald. I'll have another go with just the green and the TurquoiseEmerald to show you what I mean if I can.
All said and done it is much easier to see on the front where we are only dealing with psitticin. The attached pic is however not too good in that regard for the TurquoiseEmerald but I can assure you she is not patchy underneath at all.
Kind regards
Mike
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Mikesringnecks
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Re: Biallelic expresion

Post by Mikesringnecks »

Hi Johan
Afraid I can't put them in the photo box any more as they are working boxes so I photographed them separately in their breeding aviaries. I really can't see any more patchiness in a TurquoiseEmerald than in a Green, and the patchiness in a mature TurquoiseBlue is quite obvious.
I will do some more comparisons when the chicks arrive because I suspect that it might be more possible to see patches in a juvenile TurquoiseEmerald than in a mature bird.
Kind regards
Mike
Mikesringnecks
Posts: 218
Joined: Sun Oct 06, 2013 11:45 pm

Re: Biallelic expresion

Post by Mikesringnecks »

Hi Johan
Please find reduced photos attached. I really can't see patches in the TurquoiseEmerald but I accept that it is still in the eye of the beholder and this beholder is probably a bit biased.
Kind regards
Mike
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