CHAPTER XI. 



INHERITANCE OF BLUE COLOR, SPANGLING, AND BARRING. 



A. BLUE COLOR. 



Color-patterns are generalized, like the barring, spangling, and "blue- 

 ing"; or localized, like the wing-bar or hackle and saddle lacing. We have 

 to consider at present the method of inheritance of the former of these kinds 

 of color patterns. As is well known (Bateson, Saunders, and Punnett, 1902, 

 1903), the Blue or Andalusian fowl is a heterozygote and, as such, pro- 

 duces white gametes and also black gametes.* The "blue" is, indeed, a 

 fine mosaic of white and black. The barbules of a blue feather are seen to 

 be finely barred with alternating pigmented and unpigmented zones. The 

 pigment consists of the ordinary melanic granules of a dark sepia color. 



My original blues arose (in pen 502) from a White Leghorn hen B 

 (recognized as heterozygous but of unknown origin) , mated toablack Minorca. 

 These blues are referred to in my 1906 report. They were both females 

 and were mated (in pen 636) to a white cock (No. 340) similarly derived. 

 Of 49 ofifspring, 11, or over 22 per cent, were black and 78 per cent either 

 pure white (35 per cent of all), white with black specks (22.5 per cent) or 

 white-and-black mosaic, i. e., blue (20.4 per cent), but the latter were very 

 variable in the quaUty of the blue. Let us designate the whitening factor 

 of the White Leghorn by W (its absence w, resulting in black) and the 

 blueing by M (its absence by m). Then, assuming that the blue females 

 produce germ-ceUs MW, Mw, mW, mw, in equal numbers, and that the 

 white male produces the same, we may expect in 16 F^ offspring the 

 combinations shown in table 64. 



Table ^.^-Combinations in zygotes of the second hybrid generation of the blue strain. 



MsWj 1 white. 



MaWw 2 blue. 



MjWs 1 black. 



MmWa 2 white. 



MmWw. . . .4 white. 

 Mmwz 2 blacl£. 



mjWs 1 white. 



m2Ww 2 white. 



m2W3 1 black. 



Totals: White ten-sixteenths; black four-sixteenths; blue 

 two-sixteenths. 



The relation between the calculated and the actual percentages is as 

 follows : 



White + black specks in females: calculated, 62.5; actual, 57.5. 

 Black: calculated, 25; actual, 22.1. 

 Blue: calculated, 12.5; actual, 20.4. 



* Wright (1902, p. 401) recognizes the variability of the blues. He advises the breeder of Andalusians that: 

 "Black and white ones [offspring] can be weeded out at once; two or three months later birds absolutely too light, or dark 

 and smoky, can be selected." 



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