How common is it for the Blacks in the general population not to be E/E?
Clare, Because it is easier to get birds that are all black with E/E many of us breed for that, but some breed for ER/ER along with the required melanizers to achieve black birds.
Both E and ER enhance black shank color, but I believe with ER you can still get the preferred slate shack color while E produces black shanks.
A problem arises when fanciers buy and cross black Ameraucana LF from two lines...one E based and the other ER. They have a greater chance of producing cockerels showing silver/gold.
Now if they are also crossing both types of blacks with lavender then they are perpetuating a problem. Although there is a shank color benefit to ER/ER based black birds, it is best to only base lavender on E/E. E based lavender birds have slate shanks (lavender dilutes the black).
I\'ve heard a lot in the last few years about \"lavender splits\", but just as all blacks aren\'t the same neither are these splits and lavenders that come from them.
I told Jess in another topic that outcrossing LF wheatens from the sources he mentioned shouldn\'t be a problem, but be careful when outcrossing blacks, lavenders and some others.
Here is a bit more on the subject...
http://www.edelras.nl/chickengenetics/mutations1.htmlMl (Melanotic) is sex influenced, autosomal incompletely dominant gene. This means that heterozygote hens with only one dose of the black enhancer (Ml/ml+) show very little pheomelanin (gold or silver) on ER (birchen) base (ie acts like a dominant gene). Whereas, heterozygote roosters with only one dose of Ml (Ml/ml+) show more gold on the hackles, wing bows, etc, when ER (i.e, acts like an incompletely dominant gene). Ml homozygous (Ml/Ml) & on its own doesn\'t cover all pheomelanin areas on e+ & ER male birds (although covers a lot), & doesn\'t cover salmon areas of e+ (eg, as in Brassy Backs) & eWh hens. Therefore, other eumelanin enhancers are needed to change the gold/silver areas to black (eumelanin).