120 Colour Inheritance in Pigeons 



smaller wing coverts and other feathers. The wing-bars and the tail- 

 bar are present as in the blue. 



The colour of the so-called mealy birds is difficult to describe. The 

 ground colour is souiewhat like that of fine oat-meal ; the wing-bars are 

 reddish — approaching the colour of damp sand. The mealy birds differ 

 in two salient points from the blues — the wing- and tail-quills are, as a 

 rule, pale in colour, and the tail-bar is absent. 



The red chequered birds stand in the same relation to the mealies 

 as the blue chequers do to the blues, i.e., they are mealies with the 

 addition of chequering. The wing-quills and tail-quills are generally 

 pale in colour ; there is no tail-bar. 



The colour of the birds used being of unknown composition, the 

 results have been based on group, rather than individual, matings. The 

 calculated results have been arrived at by considering all the types of 

 gametic combinations theoretically possible, and by assuming that each 

 pair of birds produces 16 offspring. 



The experiments have led to the following conclusions : 



1. Red (of red chequer or mealy) is dominant to blue. 



2. Presence of chequering is dominant to absence of chequeiing. 



3. Red chequers may be homozygous or heterozygous for colour or 

 chequering. 



4. Mealies may be homozygous or heterozygous for colour. 



5. Blue chequers may be heterozygous or homozygous for chequer- 

 ing, but are homozygous for colour. 



6. Blues are homozygous. 



Two pairs of allelomorphic factors may therefore be considered : 

 R (domt.), presence of red. r (rec.) absence of red. 



C (domt.), presence of chequering. c (rec.) absence of chequering. 



Red chequer may then be represented by RO, blue chequer by rC, 

 mealy by Re, and blue by re. 



Group 1. Red Chequer x Red Chequer. 



Composition of parents, RGRC, RCRc, RCrC, RCrc, RcrC. 



Types of mating possible, 15. 



Number of offspring (16 from each mating), 240. 



Calculated apjDcarance : 



(240) 196 Red cheq. ; 20 Blue eheq. : 20 Mealy : 4 Blue. 

 (70-8) 57-9 : 5-9 : 5-9 : 11. 



