HISTORY OF THE CANARY 



31 



This result gives the required 50 per cent, 

 of each. 



One would expect the female of the 

 homozygous type of dark-eyed Canary to 

 be homozygous, as well as the 

 A Sugges= male, and I have evidence of 

 tion for the ^^\^[^ j,^ several of my females 

 Breeding of . . , 



Male Birds gi^'i"ff ^'^ry large percentages 

 Only. of dark - eyed males when 



mated to pink-eyed males, 

 the proportion of 6 to 1 occurring several 

 times. It is probable that a homozygous 

 dark-eyed female would be completely 

 dominant. over the cinnamon male, and that 

 male dark-eyed progeny only would result. 



I can prove the occurrence of wild 



heterozygous males by the following most 



interesting result, viz., a 



"^" family of young Greenfinches 



Interesting , . , t / i ? ,^ „ mi 



Result. which I bred m 1908. The 



father is a wild caught bird 

 that I selected as being of the colour 

 which I think indicates a heterozygous 

 nature, not only in wild birds, but also 

 in Canaries — viz., a colour I call cinna- 

 mon-green. To any casual observer, how- 

 ever, the bird would pass as a normally 

 coloured Greenfinch. The mother is one 

 of my pale cinnamon — almost creamy-white 

 — Greenfinches already mentioned. 



The family of five consisted of four cin- 

 namons and one of a greyish type, all 

 much paler than the normally coloured 

 young of Greenfinches. Unfortunately the 

 whole family died from one to three months 

 old, and on examination proved to be four 

 cinnamon cocks and one grey hen. 



Otlier characters which I have proved to 

 behave as recessives are : (a) buffness, (b) 

 crest-bred plain-headedness. 

 Inheritance fheir contrasted characters- 

 Characters. (") yellowness, (b) crestedness 

 — exhibit more or less imper- 

 fect dominance (see " Canary Breeding "). 



It is essential in studying Mendelian 

 phenomena as occurring in fancy varieties 

 that the most strict definition of the char- 

 acters under examination be made, and 

 that their nomenclature, and behaviour 

 under varying conditions be thoroughly 

 understood. 



A fancier is trained to detect differences 

 which others are quite unable to see, and 

 his success depends on the careful balanc- 

 ing of factors which to the uninitiated are 

 unobservable. 



It would therefore save much confusion 

 if sharply-defined facts only were taken into 

 consideration meantime, and if no assump- 

 tions were made with regard to technical 

 "fancy" points, which the skilled breeder 

 alone understands. 



On the other hand, it may help the 



fancier in his breeding operations if I give 



the following short account 



Mendelian ^f Mendelian inheritance with 

 Inheritance. 



an explanation of some of 



its nomenclature. The term "gamete" is 

 applied to the reproductive elements — 

 male and female — spermatozoon and ovum. 

 The cell formed by the union of a male and 

 female gamete is called a " zygote." A 

 zygote formed by the union of two similar 

 gametes (e.g., both with pure dark-eyed 

 character) is called a " homozygote," 

 while the term " heterozygote " is applied 

 to the zygote formed by the union of two 

 dissimilar gametes (e.g., one with the pure 

 dark-eyed, and the other with the pure 

 pink-eyed character). 



A simple and fairly typical case of 

 Mendelian inheritance is shown by my 

 dark - eyed male :< pink - eyed female 

 matings (Group III.). This may be more 

 easily understood by the following diagram, 

 where d stands for the pure dark-eyed 

 character, p for the pure pink-eyed charac- 

 ter, and (d) for the impure or heterozygous 

 dark-eyed character. 



d 



? 

 P 



(d) 



X — 



(d) 



(d) 



(d) 



Id 



I 

 d 



2(d) 



d (d) (d) 



Ip 



I 

 P 



i 

 P 



