Backyard Poultry Forum • View topic - Sapphire Gem genetic make up stuff

Backyard Poultry Forum

Chickens, waterfowl & all poultry - home of exhibition & backyard poultry in Australia & New Zealand
Login with a social network:
It is currently Sat Oct 23, 2021 12:29 pm

All times are UTC + 10 hours [ DST ]

Post new topic Reply to topic  [ 3 posts ] 
Author Message
PostPosted: Sat Mar 13, 2021 4:34 pm 

Joined: Sat Mar 13, 2021 1:21 pm
Posts: 3
Hello all.
(Warning! I only have a grasp on basic chicken genetics, but I learn. As it turns out after writing this post, I just needed to regurgitate some of this crap after a week of diving deep and running circles in my quest for understanding!)

Grabbed three free Sapphire Gem hens this past weekend.
I like to have a general idea of what my gene pool looks like.

It appears that the Sapphire Gem is a Blue Plymouth Rock rooster crossed to a Barred Rock hen, and a Blue Plymouth Rock appears to be a Blue Andalusian rooster crossed to Barred Rock hen.


(Blue Andalusian x Barred Rock) x Barred Rock

So what is the Blue Andalusian genotype? I am finding conflicting info. Here on BPF it is listed as:

E/E (or E^R/E^R) Bl/bl+ Ml/Ml Pg/Pg Co/Co S/S ar/ar

The conflict is that the 1991 study by Campo and Alvarez "Further Study on the Plumage Pattern of the Blue Andalusian Breed" claims to demonstrate that the Blue Andalusian does NOT carry Co/Co.
This destroys my entire understanding of Co as the gene that pushes autosomal barring (Ml/Ml Pg/Pg ?) out to the edge of the feather, creating the lacing (Ml/Ml Pg/Pg Co/Co.)
What gives? Am I just misunderstanding and oversimplifying something? Gross errors in understanding?


That addresses the Blue Andalusian confusion, now on to the Barred Rock confusion.

Genotypically, what are they? After a few days of searching through every online forum, chicken calculator, social media, Pubmed, etc. I can only find one instance of the proposed Barred Rock genotype. It was presented by a Cote study and lists the Barred Rock as:

E/E Ml/ml+ Pg/pg+ Co/co+ B/B

Granted, I fully understand that Barred Rocks can hide a plethora of genes under the E/E, which is why I suspect it was so difficult to find a Barred Rock genotype... ...nobody wanted to go out on a limb and get it wrong? (or maybe it's just so basic that nobody but me needs to see it written down?)


Extra curricular questions that arose while researching the above genotypes:

What is autosomal barring? What breeds does it express in? Is it Ml/Ml Pg/Pg without Co?

Is it true that Ml/Ml turns thin lacing into the nice thick lacing as seen in Wyandottes?
Is it also true that Ml/ml+ creates an extra wide lace know as 'over-melanized'?
Then ml+/ml+ (or lack of melanotic) must be where the thin lacing comes into play...

...but under what other pattern genes? And BTW, what are the phenotypic expression of these combos?
ml+/ml+ Pg/Pg Co/Co ?
ml+/ml+ Pg/pg+ Co/Co ?
ml+/ml+ Pg/Pg Co/co+ ?
ml+/ml+ Pg/pg+ Co/co+ ?
ml+/ml+ Pg/Pg co+/co+ ?
ml+/ml+ Pg/pg+ co+/co+ ?
ml+/ml+ pg+/pg+ probably nothing, because that simply yields 'no feather pattern', regardless of Co, yes?

So while we're at it...
8 more times for Ml/ml+
8 more times for ML/ML

and that doesn't even take into account what 'E' or 'e' background allele any of the above combinations is interacting with...


Aren't the vast majority of Ml/Ml Pg/Pg expressions linked?
Is it safe to say that:
If Ml/Ml then Pg/Pg
If Ml/ml+ then Pg/pg+
If ml+/ml+ then pg+/pg+?

That would cut down the pheno expression possibilities by what, 2/3?


This is the kind of rabbit-holing I run into as I try to expand my grade-school understanding of chicken genetics!
I'm close to throwing these 137 pages of notes away and just wait to see what the birds look like when they mate.

Let's take it up a notch on the frustration pole. They will be mating to a white silkie rooster. I'm going to need a 1600 block Punnett Square! And again with the "What is hiding beneath the white?"
And somebody in one of these forums claims that most white silkie crossings produce partridge offspring.
(I poked my head into the partridge arena and quickly pulled it out again! Holy crap! Seems like everybody has their own opinion of what a partridge genotype is, or definition of what a partridge pattern is. Ugh!)

What were we talking about?
Oh yah, Sapphire Gems!

More frustration.
One of the trio of hens has a muddy brown, tannish, dun-esque, cream-esque dirtiness to her blue that is uniform across her entire body. Never was able to figure out what kind of gold modification interacts with blue to yield a uniform full-body muddiness. Kinda want to just remove her from the breeding, but this whole thing is just for "fun??"! They are hatchmates and a pretty tight trio of pals, don't really care to stress them out like that. Mostly they are just to keep my Cream Legbar and white silkie roosters company until the breeding hens are old enough next year (chicks arriving in July.)

Might as well play with what I got, in the meantime, eh? Learn as I go.

I think I had a question...

20210311_154543cropped.jpg [ 426.02 KiB | Viewed 3091 times ]
PostPosted: Sat Mar 13, 2021 4:40 pm 

Joined: Sat Mar 13, 2021 1:21 pm
Posts: 3
Middle hen is the muddy one

20210311_154537cropped.jpg [ 1.08 MiB | Viewed 3089 times ]
PostPosted: Sat Mar 13, 2021 4:43 pm 

Joined: Sat Mar 13, 2021 1:21 pm
Posts: 3
close up

20210312_102517cropped.jpg [ 545.07 KiB | Viewed 3089 times ]
Display posts from previous:  Sort by  
Post new topic Reply to topic  [ 3 posts ] 

All times are UTC + 10 hours [ DST ]

Who is online

Users browsing this forum: No registered users and 19 guests

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to:  
Powered by phpBB® Forum Software © phpBB Group
©2004-2014 Content rights reserved