What is the difference between Extended Black and Birchen ?
- E/E (Australorp - Glu92Lys, Met71Thr) have 2 mutated amino acids,
- ER/ER (Livorno - Glu92Lys) have only 1 mutated amino acid.
It are these mutated amino acids that sent the different signals to produce eumelanine (black-pigment) :
for E/E 2 different coded signals => Extended Black phenotype
for ER/ER only 1 coded signal => Birchen phenotype
note : e+/e+ (wild-type - Met71Met, Glu92Glu, Leu133Leu, Thr143Thr, His215His) no mutated amino acids.