It is of a recent occurrence the DNA sequencing of 3 Birchen alleles, as once previously thought of as only 1 allele - ER Birchen.
Three different alleles of the melanocortin 1 receptor locus (MC1-R) :
-ER (Livorno) Glu92 => Lys
-ER (Fayoumi) Leu133 => Gln
-ER ("Funky") has the dominant wheaten mutation Thr143 => Ala and the Fayoumi birchen mutation Leu133 => Gln combined.
Cosi, certe cose misterioso non sono più un mistero !