Recessivity and masking ... the same phenomenon?

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Recio
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Recessivity and masking ... the same phenomenon?

Post by Recio » Tue Nov 19, 2013 2:30 am

Hi everybody,

From previous comments I know you were expecting this post to come, so let's go. First let me acknowledge Gratz for his open mind. I will just develop his idea with some exemples. Please, Gratz, let me know if I am wrong or if I stick to what you were meaning.

Let me tell you a tale: Some years ago a cargo with full of IRN mutations sank near an isolated island in the Pacific Ocean, far away from any other land. Birds were able to scape, reproduce and proliferate. In this island there was a special type of snake able to detect the emitted fluorescence of the birds. This snake attacked and eliminated every bird owing psittacin, but it couldn't "see" birds without psittacin, and thus, after several years all the birds in the island were Blue series birds (grey, blues, cobalts, mauves, albinos, ...). Since the island was of volcanic origin, the birds which better adapted were Grey (better camouflage) and very soon there were plenty of grey birds (95% of the total population).

Several hundred years later the island was re-discovered by the descendants of very well known ornitologists of the XXI century (Ben, Madas, Willy, Johan, ...) and they began discussing about genetics. No doubt the wild birds were grey. Could you follow their logics to adscribe an inheritance pattern to blue, cobalt, mauves and albinos birds?

It is a game, but it will give us a very important insigth about the relativeness of our system to adscribe inheritance patterns. Play the game. You will be surprised :shock:

Regards

Recio

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madas
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Re: Recessivity and masking ... the same phenomenon?

Post by madas » Tue Nov 19, 2013 2:38 am

Recio wrote: well known ornitologists of the XXI century (Ben, Madas, Willy, Johan, ...)
You made my day. :mrgreen:

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Gratz
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Re: Recessivity and masking ... the same phenomenon?

Post by Gratz » Tue Nov 19, 2013 4:24 am

Recio

First of all , thank you
Secondly Yes , you know what I mean and you are able to translate it much better than I can as I do admit I am not the best at describing what I mean in scientific terms,but I tell after this Emerald post I have learnt a lot thanks to all you gurus on this forum.
So Recio , be my guest

Regards
Gratz

trabots
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Re: Recessivity and masking ... the same phenomenon?

Post by trabots » Tue Nov 19, 2013 5:45 am

We aren't gurus. The only gurus I have come across are Terry and Deon. We are amateurs with some pretending to be scientists.

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Ring0Neck
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Re: Recessivity and masking ... the same phenomenon?

Post by Ring0Neck » Tue Nov 19, 2013 6:59 am

Willy,

I don't think you are an amature, ... or any of the named in this thread for that matter.

As for myself, my signature tells all, not to be confused with a guru ;)


I consider everyone in this forum as contributors & friends.
I'm greatful to everyone for sharing their experiences & knowledge.

Teamwork rules!


Recio & Gratz, I can see the game, nice story, very creative.
They would soon realise that grey is dominant over (masking) ... not the others recessive to,
... they would do a search and find this thread :D

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

Recio
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Re: Recessivity and masking ... the same phenomenon?

Post by Recio » Tue Nov 19, 2013 1:05 pm

Let's go:

Johan descendent had travelled to this island with his wife, a wanderfull woman with an important scientific background. In the morning, while having their coffee (it was their prefered moment of the day), they decided to analyse the blue birds respective to the wild grey birds. They knew where the nests were and which birds were the parents. They noted their observations and these are roughly their results:

Blue x Blue ..... 100% Blue birds
Blue x Grey .... sometimes 100% Grey and others 50% Grey and 50% Blue

They decided to keep the Grey birds producing 50% Blue offspring and pair them up. Next season they realized that those Grey birds produced 75% Grey offspring and 25% Blue offspring.

Johan's descendent was happy because he had just shown without any doubt that Blue was recessive respective to Grey, and viceversa Grey was dominant respective to Blue; that is Blue and Grey were different alleles of the same gene:

1. BlueBlue x GreyGrey ..... 100% heterozygous GreyBlue .... Grey phenotype
2. GreyBlue x GreyBlue ..... 25% GreyGrey, 50% GreyBlue & 25% BlueBlue .... 75% Grey phenotype and 25% Blue phenotype.
3. GreyGrey x GreyBlue .... 50% GreyGrey & 50% GreyBlue .... 100% phenotypic Grey

His wife was not that much sure: she thougth that they have just shown the interaction of Blue with its Wild allele, but other than the gene coding for Grey, so that what they were observing was:

1. BlueBlue x WildWild .... 100% heterozygous BlueWild .... Wild phenotype (Grey)
2. BlueWild x BlueWild .... 25% BlueBlue, 50% BlueWild & 25% WildWild .... 25 % Blue phenotype and 75% Wild phenotype (Grey)
3. WildWild x WildBlue .... 50% WildWild & 50% WildBlue .... 100% phenotypic Wild (Grey).

Johan's descendent asked to her wife : if Blue and Grey are not alleles of the same gene, then your 25% BlueBlue (point 2) would be expressed at the same time that the GreyGrey ... and I do not see any Grey there. How can you explain this?

That's very simple!!! Blue is masking Grey!!!

Could you please help them. Read twice before answering.

Recio

PS: Thanks to Johan's genes for helping us in this delicious task.

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Ring0Neck
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Re: Recessivity and masking ... the same phenomenon?

Post by Ring0Neck » Wed Nov 20, 2013 6:33 am

Johan's descendent asked to her wife...


I'm glad i did not leave to see those times :lol:

Jokes aside, I received a pic dated 2213
their wildtype

http://parakeet.me/irn/m/DSC_0169a.jpg
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Re: Recessivity and masking ... the same phenomenon?

Post by trabots » Wed Nov 20, 2013 7:17 am

No doubt the wild birds were grey
Could you follow their logics to describe an inheritance pattern to blue, cobalt, mauves and albinos birds?
So there are Dark, Ino and other genes as well but they survive barely and will eventually die out because the non-Grey phenotypes aren’t as well camouflaged.
he had just shown without any doubt that Blue was recessive respective to Grey, and viceversa Grey was dominant respective to Blue; that is Blue and Grey were different alleles of the same locus:
His breeding scenario is wrong as it is written as if Grey and Blue are alleles, but what he described does not point to alleles. I don’t see how this proves any allelic relationship. If they were alleles neither would be dominant or recessive to the other, all alleles of the same locus are equal genetically. Alleles are co-dominant with each other.
1. BlueBlue x GreyGrey ..... 100% heterozygous GreyBlue .... Grey phenotype
2. GreyBlue x GreyBlue ..... 25% GreyGrey, 50% GreyBlue & 25% BlueBlue .... 75% Grey phenotype and 25% Blue phenotype.
3. GreyGrey x GreyBlue .... 50% GreyGrey & 50% GreyBlue .... 100% phenotypic Grey
The above is the same as below with the substitution of ‘Grey’ with ‘Wildtype’ but as Wildtype is Grey it is exactly the same except that at 2. below you have put BlueBlue at the front and WildWild at the back, irrelevant.
1. BlueBlue x WildWild .... 100% heterozygous BlueWild .... Wild phenotype (Grey)
2. BlueWild x BlueWild .... 25% BlueBlue, 50% BlueWild & 25% WildWild .... 25 % Blue phenotype and 75% Wild phenotype (Grey)
3. WildWild x WildBlue .... 50% WildWild & 50% WildBlue .... 100% phenotypic Wild (Grey).
if Blue and Grey are not alleles of the same gene, then your 25% BlueBlue (point 2) would be expressed at the same time as the GreyGrey ... and I do not see any Grey there. How can you explain this?
You have said there is 75% Grey phenotype at 2. in both scenarios, so you have contradicted yourself by saying you see no grey phenotype at 2. in the second scenario. The phenotype outcomes are exactly the same if the mistake is ignored. That is both are worded wrong as Blue and Grey are not alleles simply because grey phenotypes had better camouflage and thus dominated the wild IRN population on the island. Therefore this exercise is moot.
That's very simple!!! Blue is masking Grey!!!
This is contradictory to your statement that “Blue and Grey are alleles of the same locus”, as if they are alleles they have to be co-dominant.

Genetically the ‘wild’ birds are 95% a mixture of GreyGrey BlueBlue combination mutants and 5% BlueBlue mutants in various combinations with other mutations. Wildtype are still Green birds, they have died out on this island due to environmental pressures.

He was wrong to treat Blue and Grey as alleles in the first set when they were not co-dominant. Selection pressures are not the same as genetics. Selection uses genetics.

She was wrong to use ‘Wild’ for Grey in the second set as ‘wild’ in this whole scenario is not a mutation but refers to any IRN on the island.

The only correct possible pairings on the island are:

1. BlueBlue x GreyGrey BlueBlue
2. GreyGrey BlueBlue x GreyGrey BlueBlue
3. BlueBlue x BlueBlue

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Re: Recessivity and masking ... the same phenomenon?

Post by Recio » Wed Nov 20, 2013 12:42 pm

Hi everybody,

I know that you all know the rigth genetics of those birds. The exercise is to deduce the genetics of those birds from their phenotype and from the breeding results, just as if you met those birds for the first time. You only need to use basic mendelian inheritance patterns. The goal is to show you that what we accept as a "golden pattern" (our "genetics") is relative and that different environements can lead us to different "genetic models".

To clarify some concepts:

1. A wild allele is the most prevalent allele of a gene in a precise time and space in the developement of a species. That is the wild allele for a species can vary in the time (allowing speciation) and in the space. It is not fixed. For this exercise I have made a quick evolutif speciation ... but the goal is not to judge speciation but our deductions from what we see.

2. Every allele of a gene has the same value and can interact with other alleles of the same gene as dominant, recessive or co-dominant in our classical meaning of the relation between alleles. In a more global meaning every allele is codominant with any other allele because the expression of each allele is independent and the final output is the composite of the effect (structural, enzimatic, ...) induced by each allele.

Is there anybody able to explain results in a different way just from the phenotypes and the pairing results, forgetting all you know about these birds? The only thing we have made is eliminate psittacins and change our reference bird (Grey wildtype).

Regards

Recio

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Gratz
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Re: Recessivity and masking ... the same phenomenon?

Post by Gratz » Wed Nov 20, 2013 2:49 pm

Here is my interpretation of this scenario, please remember at this point we know nothing about genetics feather structur etc, we are on a dull island
Ok we have 2 colours in our birds , visually , grey and blue .
We paired up two blue birds and all we breed is blue babies
We paired a grey and a blue we have bred blue and grey babies
We paired up our selected grey birds that have produce blue in the past and these two grey birds stil bred a blue although only around 1 in a clutch of 4
So we can breed blue babies from all these combinations but we can't breed a grey looking bird when we put two blues together
Is the Blue blocking the grey colour ? Is it grey but we can't see it and no matter how many blue birds we breed we can't see the grey so it must be hidden .?

Have I made sense?
Remember forget genetics or even better ask a friend or your children what they make of Recio's scenario

Cheers
Gratz

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Re: Recessivity and masking ... the same phenomenon?

Post by Johan S » Thu Nov 21, 2013 2:39 am

Recio, although I am little more than a brain in a jar attached to a robot body in 2213, I do still enjoy puzzles and aviculture. Although it feels like I should have the answers to your puzzle, I'm afraid the brain transplant has left many gaps in my memory. My descendent, Joaquin (named after a great ornitologists of the XXI century that somehow failed to make your list) sends his regards from the island. Two years ago, he also sent me some birds from the island, the wildtype grey and the very rare blue variety (found mostly in a large flock on the eastern side of the island). I am trying to confirm their breeding results, and they have assured me the grey bird also carries the illusive blue gene. This pair is my pride and joy.

Image

Some other good news, Joaquin and his wife (her name is Wilma, by the way) are extremely excited. From one of their grey birds (a chick removed from it's nest in the north east of the island) paired to a blue, a different phenotype of blue has been produced, a much darker version. I am hoping to receive a picture soon. The phenotype appears to be somewhere between the blue and grey parents. In 2211 they mentioned seeing such a bird, but they never did confirm and thought it might have been a trick of light. I'll ask them to email3.0 you their experimental set up and results.

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Re: Recessivity and masking ... the same phenomenon?

Post by Recio » Thu Nov 21, 2013 6:53 am

Hi Johan,

Great news : I have just received the pic of such strange bird.
Here it is:

Image

I am still waiting for the results of their breeding observations. They will send them later (tonigth ... European nigth :) ).

Wilma has called this little fellow "Cobalty", because of his cobalt colour, and she says that it probably consists of a combo of a new factor (she call it Dark, sacrée Wilma!!!) and Blue or Grey, but she is not sure. Could you please help her with the genetics of this factor together with Blue and Grey? We will confirm later, after receiving their results.

Thanks

Recio

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Re: Recessivity and masking ... the same phenomenon?

Post by Johan S » Thu Nov 21, 2013 10:28 am

Recio, this bottlebrain doesn't allow for much creative thinking anymore. I leave that to my ancestors. I did ask them if they were considering that the mutation was exclusively from the north eastern flock, and could be expressed in the rare blue series more common in the east, or whether it could be an even rarer activatory gene hidden by both parents that managed to turn on a previously unexpressed gene that modifies the feather structure. We can rule out the intermediate form between blue and the wildtype, as the WildtypeBlue already exists and appears like the wildtype. Such a mystery.

Recio
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Re: Recessivity and masking ... the same phenomenon?

Post by Recio » Thu Nov 21, 2013 11:09 am

Hi everybody,

This is the pairings they made and the offspring results:

1. Cobalt x Cobalt ..... 25 % Blue birds, 50% Cobalt birds and 25% Mauve birds
2. Cobalt x Blue .... 50% Blue birds and 50% Cobalt birds
3. Cobalt x Grey .... sometimes 100% Grey offspring and sometimes 25% Blue, 25% Cobalt and 50% Grey.

The first pairing (Cobalt x Cobalt) allowed them to recognize the presence of the Dark factor, producing Blues, Cobalt (Dark Blue) and Mauves (DF Dark Blue). Since every bird was Blue, or a combination of Blue and Dark, no one phenotypic Grey was produced. These results further supported the hypothesis that Blue was masking Grey. But this first pairing also fitted the hypothesis of Blue and Grey as different alleles of the same gene : since the Grey allele was not present in any parent no one Grey chick could ever be produced. So this pairing did not help to elucidate which one was rigth.

The second pairing (Cobalt x Blue) ... again no one Grey bird was produced and both hypothesis could explain the results.

The third pairing (Cobalt x Grey) produced:
3.1. 100% Grey offspring ... the conclusion was that the Dark factor is masked by Grey phenotype, but it did not allow to know if Grey and Blue are alleles of the same gene or of different genes.
Here they all agree : Grey phenotype is masking Dark ... And very quickly they knew wich hypothesis was rigth. Do you know why?

3.2. 25% Blue, 25% Cobalt and 50% Grey offspring. To be analysed later.

Recio

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Re: Recessivity and masking ... the same phenomenon?

Post by Recio » Thu Nov 21, 2013 11:33 am

Yes! I know why!

If Blue was able to mask Grey and Grey was able to mask Dark ... Blue should have been able to mask Dark. This is not true : Blue and Dark produce Cobalt ... So the hypothesis of Blue masking Grey is rejected and we keep the hypothesis of Grey and Blue as alleles of the same gene.

We could do this little game with every mutation in the blue series and stand for weeks, but this is not the goal of this post. I am going to do very quick:
I defy anyone to prove me that Grey and Blue are not alleles of the same locus (gene) without using birds owing psittacin. You can use any bird as your reference wild bird (Grey or whatever you like, but without psittacin) ... and I will be able to give you an alternative explanation of your results considering Grey and Blue as alleles of the same gene.

Who accepts the challenge?

Regards

Recio

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