Improving partridge, a cross to black and identifying mottling genes.
For Beginners
Partridge is a beautiful pattern in all chickens, but for it to be "correct" the bird needs to have two copies of a gene responsible for the pattern. This gene is called Patterning gene and has a label of Pg if it is present and pg+ if not.
pg+/pg+ shows you the gene is not present.
Pg/pg+ shows you one copy is present
Pg/Pg shows you the bird is "pure" or has two copies.
(percentages are from the Genetics Calculator)
Have a look at the patterning on the feathers below to see what i mean, both are from partridge birds, one has two copies of Pg, one has one copy of Pg. That gives us a big difference in the feather pattern on the bird. Getting this gene "pure" or having two copies is essential to get the multiple lacing or "pencilling" that is sought after in this pattern.
I bought a pair of partridge pekins because i like the pattern and had not seen many of them in South Africa.
The pair i got were young and hard to judge the genetics because the pattern had not "set" on either yet.
In the States or the UK this would be easy, all you would need to do is buy a pair from a reputable breeder and start there. I have only seen 3 partridge in over a year in South Africa, and only one pair of Silver pencilled (Same gene as partridge(Pg) but white in colour(S) as opposed to red(s+).)
There is a difference in Partridge around the world, in the USA the birds require an additional gene (Mh) or Mahogany, giving them a much richer colour(think Rhode Island Red). Here and in the UK the birds do not generally carry Mh.
The partridge in the UK may also carry the Dilute gene (Dl), giving the "dead oak leaf" colour.
-see Breeding American Partridge in the future projects section.
My first ambitious project way to improve the type of my partridge line by an initial cross to black.
My initial thoughts were, that because they are rare here, the must have been inbred or line bred heavily, so the new genes and vigour should be established at the start of the program.
So i bred my partridge cockerel to my black hens, and only hatched eggs from the black pullets for the first season. The results were largely what i expected, black chicks, with some pattern leaking into the wings and tail (see left). This leakage of pattern from the Partridge male in the chicks showed me that certain chicks had a copy of Pg(pattern gene) and those would be the ones to use in the f1 x f1 mating to get back to partridge birds. These were the birds heterozygous on the e locus or part Extended black(EE), and part Partridge(e^b)
What i didn't expect was the development of white feathers on the chest and tail of one of the black f1 cockerels. My initial thought was that one of my white hens had managed to sneak a egg under my broodies(show you how much i knew about genetics at that point), but as the boy developed i saw that something else was taking place.
This boy shows me that my partridge cockerel is heterozygous for the recessive mottling gene (mo). This recessive gene is quite hard to pinpoint, as due to it's recessive nature it does not always show unless there are two copies present in the birds, so it can crop up serveral generations down the road with no warning whatsoever. There are people who think that the gene is easy to identify in the chick down but i havent found this to be the case for me so far.
So, at this point i know that my cockerel is Heterozygous for mottling (Mo+/mo), but because mottling is recessive, one or both of my black hens must also carry one copy of the gene. Test breeding will be the only way to determine this in my future generations.
So now i can make some more educated guesses about my cockerels genetics.
I know he is a Partridge with one copy of mottling and carries at least one copy of Patterning gene (Pg)
Pg/pg+ or Pg/Pg
Mo+/mo
s+/s+
i also know that the offspring are pure s+/s+ due to both pullets being s+ black, and partridge being s+.
And i know that some carry patterning (Pg/pg+), and some carry mottling(Mo+/mo). Identifying the chicks carrying one copy of Pg is easy, as it shows in the juvenille feathers as they feather in (in my experience - test breeding will confirm),
at about 2-3 weeks it is easy to see the leakage, after that it gets covered up by black in the females.
I can make guesses on which carry mottling also by the juvenille feathers.
i wasn't going to hatch any from my partridge pair, but thought i should test out two eggs. After seeing the mottling from my Partridge cockerel and thinking the two were related my logic was that both could carry mottling.
So i put two partridge eggs under one of my broodies. Both hatched. Again i found the mottling beginning to come in. So now i knew my partridge pullet has one copy of the mottling gene. Letting the two chicks grow up i can now make a better guess at the partridge pullets genetics.
Pg/pg+
s+/-
Mo/mo+
This gives me a much better idea of what i have and what i need in order to breed partridge.
And now i know that at least 3 of my starting stock carry mottling. i know the important genes of my partridge pair.
Oddly, the chances of moving mottling onto an e^b base is very very small, due to the linkage of the mottling gene on the e locus being quite "loose" with a linkage of 1/12. So the odds of getting a mottled partridge are about 1/64 or a 1.5625% chance. I have never seen mottled partridge, or indeed any pictures of them on the internet. It is a fantastic looking gene combination though.
So my mottled partridge pullet i can say is Pg/pg+, s+/- and mo/mo.
So, to breed partridge with correct pencilling i need to either stick to my currenct cockerel and pullet.
That would give me a 1/8 (12.5%) chance of getting a correctly pencilled pullet from their breeding.
Or i can find a Pg/Pg female and increase my chances to 1/4 or 25% for a Pg/Pg pullet.
i did keep one pullet, who looked to carry Pg and split for e^b, i was hoping to back cross her to my partridge rooster to improve type on my future partridges, but she was eaten by a genet.
i may return to this project in the future, but dont want to use black at the moment. So next up i will be using my better typed whites in this seasons cross, assuming they are dominant white.