Detailed peafowl genetics discussion.

dannyB · **Posted:** Tue Sep 20, 2011 8:08 pm

Detailed peafowl genetics discussion by PeacockNSW

andrewschooks wrote:

The genetics are actually very simple. All the alleles are at the same locus.

To make it easier to follow I've used B, W, P letters to represent blue, white and pied. They have roughly that order of dominance as far as affecting phenotype.

Two white alleles at the locus = WW = white phenotype.
One white and one pied = WP = Pied with a fair amount of white on the bird. That is more than just a wing feather or two. The so-called reverse pied is a sub category of this phenotype.
Two pied alleles = PP = Blue phenotype with one to a few white wing feathers, may have a little under the chin too.
One white and one blue allele = WB = blue phenotype with odd white wing feather.
One pied and one blue = PB = Blue phenotype with a small chance of some white feathers on the wing.
Two blue alleles = BB this is a straight indian blue.

My earlier predictions are based on this information.

Thus matings of two 'Pied with fair amount of white' = PW x PW gives 25% PP, 50% PW and 25% WW. This is where the statement that Pieds never breed true come from. It is however important to be really careful to make sure that when someone is talking about Pied whether they are talking about PP or PW. This issue gets confused very often and you'll see postings on here that contradict themselves because of this issue.

There is also another complexity between what is reverse pied and regular 'pied with a fair amount of white' both are PW. Its just that reverse pied are highly selected for large amounts of white.

The genetics are actually far from being that simple and most genetics charts I have seen are oversimplified and often just wrong. The reason being that pied genetics do not follow traditional mendelian inheritance ratios but are complicated by a condition known as partial penetrance. Simplistically, whether or not a pied pairing will follow any degree of mendelian inheritance is determined by how much of that gene is expressed. Many more than 2 or 3 genes may be involved. Thankfully, Somes and Burger 1993 made it easier to understand. I would suggest anyone interested in how partial penetrance works in these cases read the article in Heredity, Vol 84, pp 57-62. It certainly clarifies why "things don't breed true".

andre · **Joined:** Tue Oct 13, 2009 5:21 pm **Posts:** 612

I don't agree 100% with your comments relating to the S & B 1993 paper, but rather than add to what is already an overheated discussion on the topic, I'll scan the paper in and post it here so people can read it for themselves.

PeacockNSW · **Posted:** Tue Sep 20, 2011 9:33 pm

dannyB wrote:

The genetics are actually far from being that simple and most genetics charts I have seen are oversimplified and often just wrong

Yes you are right as many here have posted many times

bluepeafowl · **Posted:** Wed Sep 21, 2011 7:31 am

The journals of heredity are interesting reading and maybe of value to some breeders. You can read them here http://jhered.oxfordjournals.org/conten ... l.pdf+html but you need a subscription

PeacockNSW · **Posted:** Wed Sep 21, 2011 10:09 am

Looks like you have to pay for it?

andre · **Joined:** Tue Oct 13, 2009 5:21 pm **Posts:** 612

Attachment:

S&BpaperLR.pdf [255.78 KiB]
Downloaded 269 times

Thats the Somes & Burger 1993 paper. Unfortunately I had to scan it at relatively low resolution to fit the 400 Mb limit on the size of uploads. If anyone wants a better quality version just PM me and I can email it to you.

I've posted this as it is the source of the information contained in my earlier post. Some folks have commented that the information is wrong. If so please update us all here with your evidence.

PeacockNSW · **Posted:** Wed Sep 21, 2011 4:09 pm

Detailed peafowl genetics discussion.

dannyB · **Posted:** Wed Sep 21, 2011 4:41 pm

My interpretation of the data in that article can be found in my book. This is based on crunching their numbers into a useable format. I'm happy that my tabulated version is well represented in terms of the science and I'll leave it at that.

PeacockNSW · **Posted:** Wed Sep 21, 2011 7:00 pm

Its been discussed many times here and I think I'll leave it at that too.

bluepeafowl · **Posted:** Thu Sep 22, 2011 8:01 am

The basic geno table is not in dispute we all know the basic geno for peafowl and those can find that information on many web sites including this forum. No one wrote the information is wrong Andrew and to put it back into context the original question was on phenotype and your answer was on genotype. The other correction I made to you was on reverse pied in which you said
[One white and one pied = WP = Pied with a fair amount of white on the bird. That is more than just a wing feather or two. The so-called reverse pied is a sub category of this phenotype] which it is not, that is too simplistic for example heterozygous alleles W/Wpd or W/w+/wpd does not take into account "micro" genetics. There is no need for an alternate or more plausible explanation as your basics are correct just not the inclusion of "micro" genetics to give the full details in particular regard to the reverse pieds. As I wrote to you privately I along with others including PA have more information on this but at this time will hold off on posting for now. Please keep this discussion positive and helpful as we are all a custom too.

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