Peafowl Genetics for Dummies (in other words us)

[AugeredIn]

It's really hard for me to say for sure, but I'm supposing that the peacock is Bronze Single Factor White Eye split to Pied, and the peahen is Spaulding Single Factor White Eye split to Bronze and Pied -- or the Pied and White genes are the other way around in the pair. Your Bronze Silver Pied offspring hit the lottery, and inherited two copies of Bronze, two copies of White Eye, one copy of White and one copy of Pied. If my assumption about the pair is correct, that's a 1/32 chance of occurring.

How to figure the odds? If you remember back to learning about probability math from school, you'll know that when trying to figure the odds of several things occurring together, you multiply the probabilities of each occurring. So the peacock had two copies of Bronze -- so passing on that was a given (i.e. 1). He had one copy of White Eye, so that's a 1/2 probability. He had one copy of Pied (or White, and then the hen had one copy of Pied -- I don't know how to tell apart birds split to Pied from birds split to White), so that's another 1/2 probability. 1 X 1/2 X 1/2 = 1/4 on Dad's Side. Mom was split to Bronze, so she had a 1/2 chance of passing that on. Mom also had one copy of White Eyed (from what I've read, it's hard to spot them from "normal" hens, but I'm not sure), so she had a 1/2 chance of passing that on. And Mom also had one copy of White (or Pied), and that's another 1/2 probability. So 1/2 X 1/2 X 1/2 = 1/8. Then multiply that by Dad's probability. 1/4 X 1/8 = 1/32 chance of all those things lining up.

Yes, I agree with your odds as calculated and your thoughts on the true genetics of the parents. The breeder has confirmed that split pied was a possibility in the male.

We were lucky.

 

[Rosa moschata]

Rosa, I have to ask. Were your parents truly clever or is your handle a reference to one our favorite late summer scents?

The dusting we are referring to is a silvery sheen on the back and wing feathers. I cannot make it show up well in pictures but it is obvious in person.

I also am not a fan of white or nearly all white birds. Why blot kurt the beautiful colors in the eye? I am forced to realize that others really like these birds and thus we can sell them easily to help with the farm expenses.

I hope conner hills returns to the discussion. I want to understand whether silver pied is an allele to white eye.

My name is Christopher. 'Rosa moschata' is one of the 70-something roses I planted in my new garden, and it will be featured prominently in my little rose hybridizing hobby.

I'm wondering if this "silvery sheen" is merely an effect of all the "eraser" genes being present together at almost-maximum levels ("maximum" level being an all-white bird), rather than resulting from a separate gene.

Silver Pied is a name given to birds based on how they appear, i.e. a phenotype. It is not based on one mutated gene, but the interaction of several (Pied, White and White Eyed). Thus it is inaccurate to say there is a "Silver Pied gene". It would be like saying there is an "Oaten" gene, when "Oaten" is really the (now less-commonly used) name given to a specific phenotype, resulting from the interaction of the Cameo and Blackshoulder genes. As such, a bird isn't "split to Oaten" but rather would be either "split to Cameo and Blackshoulder" (males only), "Cameo split to Blackshoulder", or "Blackshoulder split to Cameo" (males only).

When you give a phenotype name to something resulting from the interaction of more than one mutated gene, you create confusion when that phenotype name is inserted into genetic calculations as though it is a single-mutation. This is why, with cage-birds, names are given based upon their genotypes. For example, we say a cockatiel is "Yellow-Faced Lutino Pearl" because it identifies the three different mutations visible in the bird, and thus the mutations responsible for its phenotype. We don't make up a new name like "Lemon Lace". Unfortunately, that practice is not common in poultry, and as a result, people keep asking questions about "what do I get when I cross this with that?" because the names given to varieties have little or nothing to do with the genetics responsible for their phenotypes.

Think of chickens -- some breeds say "Lavender" while others say "Self-Blue" yet both refer to the same gene. No wonder there is confusion. In cage-birds, there is standardization across different species. A sex-linked mutation resulting in the deletion of melanin but retention of yellow-red pigments is ALWAYS called "Lutino", be it in a budgie, a cockatiel, an amazon, a conure, etc. Such a standardization allows people familiar with the genetics of "Lutino" in one species to apply the same rules of inheritance to "Lutino" in another.

 

[Arbor]

Arbor,I spoke with Clifton about this progressive pied many years ago already.What he told me was not good.He tried for years to get offspring from that male and hens that would "progress" and turn white.He was never sucessful by using the direct bird,or linebreeding offspring. He says it was a fluke,or freak of nature.Interesting to say the least, but a 1in a million bird. I heard some of these offspring was bought and is up in Wisconsin and Minnesota now and noone has been able to get this rare genetic matchup to occur again.It would seem to me that the pigment gene of white was actually masked by bronze.Possibly as molting occured and new feathers grew in the masking gene got weaker and the white came to be. So since no known offspring has came about resembling the male,it should have just been put on display in a zoo.And why would anyone try to keep breeding a bird to replicate known health-poor genetic traits such as blindness?

The gentleman in NY still has hens that exhibit this characteristic which seem to pass it on to their offspring. As the bird ages to maturity (and beyond) they increase in the amount of white through each moult. I too think this is somewhat of a fluke, and I don't really agree with marketing it as a new colour/pattern if it seems both unstable (and quite variable) and the cause of future health problems.

 

[Rosa moschata]

The gentleman in NY still has hens that exhibit this characteristic which seem to pass it on to their offspring. As the bird ages to maturity (and beyond) they increase in the amount of white through each moult. I too think this is somewhat of a fluke, and I don't really agree with marketing it as a new colour/pattern if it seems both unstable (and quite variable) and the cause of future health problems.

It's also possible that the visible effects of this "condition" are just part of something greater, which would otherwise be called a (possibly) heritable disease. Perhaps it really is something akin to vitiligo in humans, perhaps it is a susceptibility to progressive melanocyte death. It makes me think about how breeders struggle with Charcoal peas. We look at them as simply a color mutation, but then it also results in reduced fertility in hens. Perhaps the color difference we see in Charcoal peas is really just a visible symptom of a genetic disease. Remember, genes encode for proteins -- and more often than not, those proteins perform multiple functions in growth and metabolism. It's not simply a case of a "black feather gene" but rather a gene which makes a different version of a protein, which in the course of various chemical processes within the peas, results in black feathers. As can be seen in visual Charcoal hens, that protein also does something else, which apparently interferes with fertility. We may call it the "Charcoal mutation" because that is the most readily apparent effect of the mutation, but on the inside, it might better be called the "female infertility mutation" which has a visual "symptom" of dark feathers.

 

[Arbor]

It's also possible that the visible effects of this "condition" are just part of something greater, which would otherwise be called a (possibly) heritable disease. Perhaps it really is something akin to vitiligo in humans, perhaps it is a susceptibility to progressive melanocyte death. It makes me think about how breeders struggle with Charcoal peas. We look at them as simply a color mutation, but then it also results in reduced fertility in hens. Perhaps the color difference we see in Charcoal peas is really just a visible symptom of a genetic disease. Remember, genes encode for proteins -- and more often than not, those proteins perform multiple functions in growth and metabolism. It's not simply a case of a "black feather gene" but rather a gene which makes a different version of a protein, which in the course of various chemical processes within the peas, results in black feathers. As can be seen in visual Charcoal hens, that protein also does something else, which apparently interferes with fertility. We may call it the "Charcoal mutation" because that is the most readily apparent effect of the mutation, but on the inside, it might better be called the "female infertility mutation" which has a visual "symptom" of dark feathers.

How would this be if some charcoal Spalding hens have been found to lay fertile eggs?

 

[AugeredIn]

My name is Christopher. 'Rosa moschata' is one of the 70-something roses I planted in my new garden, and it will be featured prominently in my little rose hybridizing hobby.
We have hundreds of Musk Rose plants running wild.

I'm wondering if this "silvery sheen" is merely an effect of all the "eraser" genes being present together at almost-maximum levels ("maximum" level being an all-white bird), rather than resulting from a separate gene.
This eraser, the silvery sheen, appears on birds that are both split white and white eye. See my comments below on silver pied being a separate gene.


Silver Pied is a name given to birds based on how they appear, i.e. a phenotype. It is not based on one mutated gene, but the interaction of several (Pied, White and White Eyed). Thus it is inaccurate to say there is a "Silver Pied gene". It would be like saying there is an "Oaten" gene, when "Oaten" is really the (now less-commonly used) name given to a specific phenotype, resulting from the interaction of the Cameo and Blackshoulder genes. As such, a bird isn't "split to Oaten" but rather would be either "split to Cameo and Blackshoulder" (males only), "Cameo split to Blackshoulder", or "Blackshoulder split to Cameo" (males only).
I am not 100% sure of the veracity of the first sentence. I am not questioning your understanding just the simple truth. The post earlier by Blue Creek Farm clearly shows a pied white eye bird that does not have silver colored feathers throughout the saddle area. My silver pieds have silver colored feathers in this area as opposed to the natural color except my cameos. They are somewhere in between. I am back to believing that connerhills is correct in that the silver pied mutation is an allele to white eye. A slightly different mutation in the same pair. Some of the big breeders certainly espouse this position through implication if nothing else. There are certainly a couple advertising pied white eye birds separate from silver pied.

When you give a phenotype name to something resulting from the interaction of more than one mutated gene, you create confusion when that phenotype name is inserted into genetic calculations as though it is a single-mutation. This is why, with cage-birds, names are given based upon their genotypes. For example, we say a cockatiel is "Yellow-Faced Lutino Pearl" because it identifies the three different mutations visible in the bird, and thus the mutations responsible for its phenotype. We don't make up a new name like "Lemon Lace". Unfortunately, that practice is not common in poultry, and as a result, people keep asking questions about "what do I get when I cross this with that?" because the names given to varieties have little or nothing to do with the genetics responsible for their phenotypes.

Think of chickens -- some breeds say "Lavender" while others say "Self-Blue" yet both refer to the same gene. No wonder there is confusion. In cage-birds, there is standardization across different species. A sex-linked mutation resulting in the deletion of melanin but retention of yellow-red pigments is ALWAYS called "Lutino", be it in a budgie, a cockatiel, an amazon, a conure, etc. Such a standardization allows people familiar with the genetics of "Lutino" in one species to apply the same rules of inheritance to "Lutino" in another.

See comments above.

 

[AugeredIn]

How would this be if some charcoal Spalding hens have been found to lay fertile eggs?

Arbor, I believe the reference is being presented as an example not as fact.

Another suggestion which is probably closer to the truth is that some of the phenotypes we see are not single gene pair mutations but mutations of multiple gene pairs or a segment of the code if you will. We tend to think of say the bronze color mutation as the mutation of a single gene pair. This may not be the truth. It might be that it is the mutation of multiple gene pairs. We don't know because the mutated gene pairs are passed along just like normal gene pairs. In the case of charcoal it is possible the mutation event affected not just gene pairs related to colors but other "stuff" as well. The other stuff in this case being a hens ability to produce a viable egg.

I would point out that the explanation I present also has holes because theoretically it could affect split charcoal hens as well and it does not.

 

[Rosa moschata]

How would this be if some charcoal Spalding hens have been found to lay fertile eggs?

India Blue and the various Greens are different species. The differences between them go beyond simple color and pattern -- while still similar, they will also have some metabolic differences. Closely-related species will have similar proteins in their blood, tissues, etc. but there are often subtle differences. For example, analyzing differences in hemoglobin across species is one of many tools used to determine how closely related different species are. Yes, there are many variations of the hemoglobin molecule across species, even if they all perform the same function.

It's possible that the India Blue "version" of some protein which is necessary for female fertility is inhibited or experiences interference from a protein associated with the Charcoal mutation -- but that the version produced by the various Greens does not encounter this interaction. It can be a subtle difference in amino acid sequence which would still allow for the different versions of the protein to perform the same function associated with female fertility, but perhaps the difference results in some sort of "lock and key" combination that fits with the altered-from-normal Charcoal protein in the India Blue version. And then in India Blues, the Charcoal protein binds up with the necessary protein required for female fertility, resulting in a severely diminished amount of that protein available for normal female fertility function.

It's really not possible to make definitive statements without laboratory investigation. But, perhaps, if the Green version shows no or only reduced interference with female fertility, progressive introgression of their version of the gene into the captive India Blue population may eventually solve the problem. In other words, the fertile female Charcoals which otherwise appear "regular" India Blue in body type will have to have a dash of Green in their ancestry in the future.

 

[Rosa moschata]

We have hundreds of Musk Rose plants running wild.

This eraser, the silvery sheen, appears on birds that are both split white and white eye. See my comments below on silver pied being a separate gene.


I am not 100% sure of the veracity of the first sentence. I am not questioning your understanding just the simple truth. The post earlier by Blue Creek Farm clearly shows a pied white eye bird that does not have silver colored feathers throughout the saddle area. My silver pieds have silver colored feathers in this area as opposed to the natural color except my cameos. They are somewhere in between. I am back to believing that connerhills is correct in that the silver pied mutation is an allele to white eye. A slightly different mutation in the same pair. Some of the big breeders certainly espouse this position through implication if nothing else. There are certainly a couple advertising pied white eye birds separate from silver pied.

1) The name "Musk Rose" has often been given to similar but different roses through the ages, including Rosa moschata, R. arvensis, R. brunonii, and others. I'm thinking the "hundreds running wild" by you are actually Rosa multiflora, which is becoming something of a "weed" in the US. In general, they have clusters of white flowers (the only US native, Rosa setigera, is unusual in the group, being pink) and give off a type of "musk" scent (to my nose, it smells just like cloves) which floats on the air, being released from the stamens more than the petals. As such, the most fragrant "musk" roses are those with the fewest petals. The true Rosa moschata differs from others often called Musk Rose in that it really doesn't exist in the wild in the form we know -- all examples found today are clones, with three flower forms (single, double, and very-double Temple). It was probably an aberrant example of a form of Rosa brunonii which didn't grow to become a massive tree climber, instead being dwarfer and blooming far longer (in South Florida, for example, Rosa moschata blooms nearly year-round). This rose featured in the ancestry of the Damasks (bred with Rosa gallica and Rosa fedtschenkoana) and the Noisettes (bred with the China 'Old Blush' and later with the now-extinct Tea 'Park's Yellow'), and through those two old groups, virtually all modern roses. My little hobby involves remaking these two groups from scratch, using different cultivars of Gallicas, Chinas and Teas and seeing what I get. I also managed to snag the hard-to-find Rosa fedtschenkoana, as well as lots of cultivars known for fragrance, mostly antiques.

2) and 3) There may be a separate gene resulting in the "silver sheen" but what I meant about there not being a single "Silver Pied gene" referred to the whole picture of what a Silver Pied pea is, which requires a copy of Pied, a copy of White, and all white ocelli. If there really is a separate gene for the "silver sheen", then simply having the "silver sheen" will not make the bird Silver Pied. It must also have loud splashes of white, and have all white ocelli, which require additional genes. That's why I think it's incorrect to say "Silver Pied Gene". If there really is a separate gene which generates the "silver sheen" then that gene should be called "Silver Sheen" to avoid confusion.

 

[Rosa moschata]

Arbor, I believe the reference is being presented as an example not as fact.

Another suggestion which is probably closer to the truth is that some of the phenotypes we see are not single gene pair mutations but mutations of multiple gene pairs or a segment of the code if you will. We tend to think of say the bronze color mutation as the mutation of a single gene pair. This may not be the truth. It might be that it is the mutation of multiple gene pairs. We don't know because the mutated gene pairs are passed along just like normal gene pairs. In the case of charcoal it is possible the mutation event affected not just gene pairs related to colors but other "stuff" as well. The other stuff in this case being a hens ability to produce a viable egg.

I would point out that the explanation I present also has holes because theoretically it could affect split charcoal hens as well and it does not.

We suppose a difference in phenotype is the result of one gene difference because of how inheritance of that phenotype behaves. If a phenotype requires more than one genetic mutation, and those mutations are had on separate chromosomes, then independent assortment would separate them out when crossing two birds split to that phenotype -- thus the inheritance pattern would not follow that of a single-gene mutation, and we would dismiss that notion of how the phenotype arises. From all I've read, Silver Pied X Silver Pied does not result in 100% Silver Pied, but rather three different phenotypes assorted into the classic 1:2:1 ratio of a monohybrid cross. OK, so you many say that's because they need to be heterozygous White/Pied. Well, that alone tells you it requires more than one gene -- not counting White Eye. As a result of observing that pattern of inheritance, the Silver Pied phenotype is NOT the result of one gene mutation. There may be an additional gene in the mix which adds the "silver sheen" but there is no one, single gene which is all that differs between "normal" India Blue and Silver Pied, as there is with Bronze, or Black Shoulder, or Cameo, or Midnight, etc. That's what I mean by there not being one "Silver Pied gene". That's my point.