. Carnegie Institution of Washington publication. 12 INHERITANCE OF CHARACTERISTICS IN DOMESTIC FOWL. B. VARIABILITY OF THE Y COMB AND INHERITANCE OF THE VARIATIONS. As already stated, the proportions of the median and the lateral ele- ments in the Y comb are very variable; the median element may, indeed, constitute anywhere from 100 per cent to 0 per cent of the entire comb. Even full brothers and sisters show this variability. Thus the offspring of No. 13 9 Single-comb Minorca and No. 3 c? Pohsh have the median element of the Y comb ranging from 0 per cent to 70 per cent of the whole comb. N
. Carnegie Institution of Washington publication. 12 INHERITANCE OF CHARACTERISTICS IN DOMESTIC FOWL. B. VARIABILITY OF THE Y COMB AND INHERITANCE OF THE VARIATIONS. As already stated, the proportions of the median and the lateral ele- ments in the Y comb are very variable; the median element may, indeed, constitute anywhere from 100 per cent to 0 per cent of the entire comb. Even full brothers and sisters show this variability. Thus the offspring of No. 13 9 Single-comb Minorca and No. 3 c? Pohsh have the median element of the Y comb ranging from 0 per cent to 70 per cent of the whole comb. Notwithstanding this variability of the median element in any family there is a difference in the average and the range of variability in families where different races are employed. Thus the offspring of two Pohsh XMinorca 240 230. PERCENTILE GRADES OF MEDIAX ELEMENT IN THE Y COMB. FiQ A.—-The frequencj' of the different forms of Y comb, each form being based on the percentage of the median element of the Y comb to the entire length of comb. crosses show an average of 46 per cent of the median element in the comb; the HoudanX Minorca cross gives combs with 60 per cent of the median element; and in the combs of the offspring of two HoudanX White Leg- horn crosses there is, on the average, 71 per cent of the median element. The HoudanX Dark Brahma (pea comb) gives combs with an average of 87 per cent median element and the Polish x Rose-comb Minorca cross gives 89 per cent median. The rose-combed hens used in this last cross were heterozygous, having single comb recessive; consequently they pro- duced also chicks with typical Y combs. Such had, on the average, only 59 per cent of the median element and were thus in striking contrast with the shghtly split rose combs. In the case of the partially split rose combs the median element ranged from 60 per cent to 100 per cent of the whole length of the comb; but in the spUt single combs the range is from 0 to 100. Please note that th
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