Peafowl 201: Further Genetics- Colors, Patterns, and More

[Rosa moschata]

Just wondering. So if one Z is purple and the other Z cameo which color is expressed. Also can a purple cameo produce a peach?

If one Z has Purple and the other has Cameo, the peacock would appear IB. Genetically, it would be IB split to Purple and Cameo, which would be different from an IB split to Peach, aka IB split to Purple-Cameo. Why? Because of where the mutations are located, and the probabilities of how they would be passed on. In terms of what they could produce, they'd be the same -- both could have Purple, Cameo, and Peach daughters with an IB hen. The difference would be that for an IB split to Purple and Cameo -- which was your example -- crossover would have to occur at a point between the loci for Purple and Cameo on the Z to produce a newly combined Z with both. Based on the original story of how the first Peach peafowl were produced, this doesn't seem to be a rare thing, hinting that the two mutations are far apart on the chromosome. But it would probably be more likely that more daughters would be Purple or Cameo, with a few being Peach or IB. With an IB split to Peach -- meaning one Z with neither and one Z with both -- the reverse would be the case, meaning he'd be more likely to have more Peach and IB daughters than Purple or Cameo.

A Purple-Cameo is a Peach. If a female has a copy of Purple and Cameo -- which would have to be on the same Z, since hens have only one -- she would be Peach.

Peach is what happens when Purple and Cameo are both visual. For Purple or Cameo to be visual in a male, he must have two copies of the respective mutation. If a male has Purple on one Z and Peach on the other, he'll look Purple -- because he has two copies of Purple, one of which is on a Z which also has Cameo on it. But he won't look Peach, because he has only one copy of Cameo. The reverse would also be true if a male had one Z with Cameo and the other with Peach -- he'd look Cameo, since he has two copies of that. But he won't look Peach, because he has only one copy of Purple.

To show Peach, a male must have both Purple and Cameo on both Zs. Genetically, that would mean being homozygous for both Purple and Cameo.

 

[Rosa moschata]

In case it may be confusing why a peacock with Cameo on one Z and Purple on the other would look IB, I'm coming back again.

OK, imagine you're looking at a Z chromosome's genes. The "Purple gene" is really a mutation of another gene, and this mutation results in "something going wrong" in the pathway leading to normal IB color expression -- instead of IB, the result is Purple. If a male has only one Z with this mutation, his other Z with the normal version of that gene makes enough of whatever ingredient was necessary to complete the IB color expression -- thus the Purple color doesn't show through. Same goes with Cameo -- if a male has only one Z with this mutation, his other Z makes enough of whatever was missing or altered by the mutation so that normal IB color shows through.

OK, so now we have a male with Cameo on one Z and Purple on the other. Why does he look IB? Because along with Cameo on one Z, he also has the "normal" version of the gene of which Purple was a mutation -- so that "normal" version compensates for what the Purple mutation altered. And the same goes for the other Z -- along with Purple, there's also the "normal" version of the gene of which Cameo is a mutation. As long as there's one "normal" version of the gene, the recessive mutation won't show.

Another way to say it is that one Z has Cameo and non-Purple, and the other Z has non-Cameo and Purple. Both Cameo and Purple are "blocked" from being visible by there being a respective "non-" version on the other chromosome. With both mutations "blocked", the result is a visual IB.

 

[EyeKeyYou]

If one Z has Purple and the other has Cameo, the peacock would appear IB. Genetically, it would be IB split to Purple and Cameo, which would be different from an IB split to Peach, aka IB split to Purple-Cameo. Why? Because of where the mutations are located, and the probabilities of how they would be passed on. In terms of what they could produce, they'd be the same -- both could have Purple, Cameo, and Peach daughters with an IB hen. The difference would be that for an IB split to Purple and Cameo -- which was your example -- crossover would have to occur at a point between the loci for Purple and Cameo on the Z to produce a newly combined Z with both. Based on the original story of how the first Peach peafowl were produced, this doesn't seem to be a rare thing, hinting that the two mutations are far apart on the chromosome. But it would probably be more likely that more daughters would be Purple or Cameo, with a few being Peach or IB. With an IB split to Peach -- meaning one Z with neither and one Z with both -- the reverse would be the case, meaning he'd be more likely to have more Peach and IB daughters than Purple or Cameo.


A Purple-Cameo is a Peach. If a female has a copy of Purple and Cameo -- which would have to be on the same Z, since hens have only one -- she would be Peach.


Peach is what happens when Purple and Cameo are both visual. For Purple or Cameo to be visual in a male, he must have two copies of the respective mutation. If a male has Purple on one Z and Peach on the other, he'll look Purple -- because he has two copies of Purple, one of which is on a Z which also has Cameo on it. But he won't look Peach, because he has only one copy of Cameo. The reverse would also be true if a male had one Z with Cameo and the other with Peach -- he'd look Cameo, since he has two copies of that. But he won't look Peach, because he has only one copy of Purple.


To show Peach, a male must have both Purple and Cameo on both Zs. Genetically, that would mean being homozygous for both Purple and Cameo.

Makes sense now, thanks.

 

[PhoredaBurds]

How do Hazel and Indigo differ? I've read separately that they're both the result of a bird carrying purple and bronze, but pics of them look different. Any info out there on these colors?

 

[Birdrain92]

Probably just the way they express themselves

 

[Birdrain92]

I understand but a little confused though I think I could fill in the blanks I'm sure. The issue I'm having is each parent gives only one chromosome. So the Cameo and Purple gene are on different chromosomes. My guess is how they cross over is during meiosis some genes cross over. Which means 1/4 of the sperm cells carry Peach. Not sure if this is accurate but this is one of the only things I can think of. Or what I used to believe is that because the genes are mutated they're already unstable and makes it easier for new mutations to happen. I think it was Brad Legg that said it, but the point being is, new mutations appear more often when using split peafowl.

 

[Midnightman14]

Peach = Purple and Cameo on the same Z chromosome. For Peach males, that means each Z has both Purple and Cameo on it. Thus all his offspring will inherit a Z with both. But if you took an IB male split to Peach and bred it to any female, you could get Peach, Purple, and Cameo daughters. This is because a split to Peach male has one Z with both Purple and Cameo, and the other Z with neither. During meiosis in spermatogenesis, the two Zs will crossover, and it's possible for the Purple and Cameo to separate ONLY in split males -- since they have one Z with neither mutation -- resulting in some Zs with just Purple and others with just Cameo. Crossover still happens in Peach males, but when it does, the result is still Peach, since each Z already has Purple and Cameo on it.




Indigo being a combination of Bronze and Purple means that offspring will inherit each color independently -- the two mutations responsible are on different chromosomes, unlike the Peach combination. See Mendel's Law of Independent Assortment, which doesn't apply to Peach because they are linked on the same chromosome. This means that if you bred an Indigo male to an IB female, you'll get Purple split to Bronze females and IB split to Purple and Bronze males. Those offspring will not pass on Indigo as one unit. Male offspring being split to two mutations have just a 25% chance of passing on both to the same offspring. Here's the math:

50% chance of passing Purple, 50% chance of passing non-Purple
50% chance of passing Bronze, 50% chance of passing non-Bronze

In probability, determining the chance of two separate things occurring together means multiplying together the probabilities of each occurring independently.

50% X 50% = 25% chance of passing Purple AND Bronze

If I had a split to Indigo (i.e. split to Bronze and Purple) male, I'd pen it with a Bronze female. Doing so would mean 25% of the daughters would be Indigo. This would be the only way to get Indigo offspring without having a hen with at least one copy of both mutations.

There can't be a "split to Indigo" female. What you CAN have is a Purple split to Bronze female. This would be the only way a female not visually Indigo could produce an Indigo son -- and only if paired with a male with at least one copy each of both Purple and Bronze.

But how would that work since you can't have a bird exhibit a recessive color and still be split to something else? Ex. I can't have a midnight bird that's split to cameo since both are recessive and cannot be expressed unless there are 2 copies of the gene.

 

[Birdrain92]

How genes can cross during meiosis is the chromosomes will line up in two lines. The two parts of the chromosomes closest to each other will sometimes exchange genes. Then the chromosomes get split, one row in one cell the other row in the other cell. Than the cell splits the chromosomes in half leaving 4 cells. Leaving 25% chance the chromosomes have two genes on one chromosome in a certain way.

 

[Rosa moschata]

I wonder if the difference could be the result of degree of Green blood between the two lines. Or perhaps there's some other subtler modifying genes Clifton selected among his breeders. Maybe there's another mutation in there, like Midnight. I emailed with him a few years back when I was first asking about combining colors in peafowl, and I'll have to search through my inbox for those messages. This was before the Indigo was announced on his website, and back when people here said combining colors wasn't possible. Clifton looked at his birds and paired them with the intent of creating living works of art -- that's how he got Peach from mixing Purple and Cameo -- and searching through offspring for something new. He mentioned another combination project but I don't remember which mutations he was using. I suppose it may be possible that if he retained splits which looked IB in his projects, he may have inadvertently thrown another mutation into the mix, and that may be the cause of the differences. Maybe his "Brown-Wing" could be in there somehow.

 

[Rosa moschata]

But how would that work since you can't have a bird exhibit a recessive color and still be split to something else? Ex. I can't have a midnight bird that's split to cameo since both are recessive and cannot be expressed unless there are 2 copies of the gene.

You are incorrect -- you certainly CAN have a Midnight bird split to Cameo. They are separate genes on different chromosomes -- Cameo on Z, and Midnight on one of the others. You can also have a bird which is Midnight-Cameo -- two copies of Midnight and two of Cameo for males, or two copies of Midnight and one of Cameo for females.

The only time you can't have something exhibiting a mutation AND being split to another is if both mutations are alleles. This means that the mutations are of the same gene, like White and Pied. In that case, there are three versions of that gene -- Normal, White, and Pied. Peas can have only two. Being White means having two copies of White, which means there isn't a spot left for being "split to Pied".