BLUE ANDALUSIAN HEN (C2032) CHANGING TO WHITE 
This hen, fromthe University of Wisconsin Poultry Department, was considered in the spring of 
1917 to bea norma! blue Andalusian. 
In October of the same year white feathers appeared on her 
neck. The illustration shows her as she appeared December 20, 1917, after completing that 
season’s molt. Photograph by James Machir. 
The particular interest in the case in 
hand arises not alone from the fact that 
the subject changed color but that in 
addition her ancestry and breeding per- 
formance are known. 
As shown by Lippincott (1918) blue 
Andalusians are usually of the genetic 
constitution PP (Re) (rE). Pisa fac- 
tor necessary for the production of 
black pigment. Its allelomorph # pro- 
duces a recessive white. R is a domi- 
nant, acting on black pigment, restrict- 
ing its distribution in such a way as to 
give a characteristic bluish gray appear- 
ance. £ is a dominant factor render- 
(Fig. 1.) 
ing an individual carrying P self col- 
ored. Self-blue is the result of the 
combined action of R and £ on black 
pigment. For reasons developed in the 
paper noted, and in a further paper 
soon to be published, it appears reason- 
able to assume that R and £ are each 
closely, perhaps completely, linked to 
the allelomorph of the other, hence 
written (Re) and (rE). 
As shown earlier by Bateson and 
Punnett (1906), when blue Andalusians 
are mated inter se they produce blacks, 
blues, and white-splashed, in the ratio 
of 1 to2 to1. Genetically the reason 
