Hello,
My spouse is interested in Ameraucanas & has joined this forum. I know a bit about genetics, but not much about Ameraucanas. I hope you do not mind if I comment on this thread.
Laced blues can be on E or ER. Blue Orpingtons are laced, but on E. The patterns on ER talked about in \"Chicken Colours\" refers to the eumelanin (black pigment), being pushed to the edges of the feathers. This allows pheomelanin (colour), such as gold or silver to show as in gold or silver laced sebrights. In order to produce that type of lacing on an ER bird, dark brown columbian (Db) is necessary, as well as the usual genes necessary for lacing (Co, Pg-Ml). It is the Co, Pg-Ml which would give the lacing on blue, without pushing all of the eumelanin to the edge of the feather on ER birds, & should have the same effect on E birds too.
In my experience many black birds carry pattern gene (Pg), as well as the obvious melanotic (Ml). I have recreated laced Orpingtons without leaving the breed by crossing blacks (Ml-Pg) with buffs (most likely Co & Db). As I was not trying to improve lacing in blues, that is where any similarity to your project ends.
If I were doing your project, while waiting for your Andalusians, I\'d try breeding a black Ameraucana with a buff or a columbian (assuming you have them in your breed) & see what happens. If you can stick within the breed it makes maintaining type so very much easier.
I am not sure whether this has been previously mentioned, but Pg, Ml & Db have linkage, (reasonably close together on the same chomosome), so the genes will most often be inherited together. A first cross between a black, hopefully, carrying Pg, & a buff, would be Pg-Ml-db+/pg+-ml+-Db, Co/co+, which ought to make selecting in future generations a bit easier (you\'d be selecting for homozygous Pg-Ml-db+ & Co) & with a cross to columbian, one would not need to think about Db. I\'m sure anyone can easily select away from wheaten (eWh) or brown (eb).
When breeding blues, it seems most sensible to breed blue to blue. That way, one can see what one is selecting; if using splash there is no way to tell whether it carries genes necessary to help or hinder. As someone else said, if all the birds carried the necessary genes there would be no need to breed to splash.
Single combs are very easy to breed out, while white in ear lobes is much less so.
I\'d give Marans a miss, as that would really mess up egg colour, introduce leg feathering, & possibly skin colour (sorry I don\'t know the correct skin colour for Ameraucanas). Also, while blue Marans, in USA, may, or may not, have lacing, the French copper blues do not, and I have never seen a Marans with proper lacing, only edging.
Regards
krys109uk