20 



INHERITANCE OP CHARACTERISTICS IN DOMESTIC FOWL. 



many as 6 toes on one foot. This result is not to be explained as due to a 

 regression towards the 4 4-toed condition, but rather as due to the inter- 

 mediate condition of the heterozygote. For 80 per cent of the hybrids 

 show either the typical or the reduced D type on one or both feet, although 

 neither parent exhibits these types. 



We have next to consider the results of mating together the F, hy- 

 brids. Table 11 gives the results of all matings of this sort. 



Table 11. Frequency of the various types of toes in the second hybrid generation between normal 

 and extra-toed races. Lettering as in table 10. 



A. HOODAN CROSSES (FiXFi). 



Serial 

 No. 



1 



2 



3 



4 



6 



6 



7 



8 



9 



10 



11 



12 



13 



14 



IS 



Pen 

 No. 



631 

 728 

 631 

 637 

 631 

 631 

 631 

 519 

 637 

 637 

 631 

 637 

 631 

 519 

 619 



Mother. 



No. 



429 



174 



448 



629 



430 



504 



174 



85 



569 



797 



86 



685 



84 



84 



86 



Races involved. 



Houd.XWh.Legh. 



....Do 



Do 



Houd.xMin 



Houd.XWh.Legh. 

 Wh.Legh.XHoud. 

 Houd.XWh.Legh. 



....Do 



Houd.xMin 



....Do 



Houd.XWh.Legh. 



Houd.xMin 



Houd.XWh.Legh. 



....Do 



Wh.Legh.XHoud. 



Totals (380) . 

 Percentages . 



No. 



of 



toes. 



5-5 

 5-5 

 5-5 

 5-5 

 4-4 

 5-6 

 6-6 

 4-5 

 5-5 

 5-5 

 4-4 

 4-4 

 4-4 

 4-4 

 4-4 



Father. 



No. 



83 



258 



409 



570 



83 



83 



83 



83 



670 



670 



83 



570 



83 



83 



83 



Races involved. 



Wh.Legh.XHoud.. 



....Do 



. ...Do 



Houd.xMin 



Wh.Legh.XHoud.. 



....Do 



....Do 



....Do 



Houd.xMin 



....Do 



Houd.XWh.Legh.. 



Houd.xMin 



Houd.XWh.Legh.. 



....Do 



Wh.Legh.XHoud.. 



No. 



of 



toes. 



4-4 

 5-5 

 4-4 

 4-4 

 4-4 

 4-4 

 4-4 

 4-4 

 4-4 

 4-4 

 4-4 

 4-4 

 4-4 

 4-4 

 4-4 



OCFspring. 



Types of toes. 



4-4 4-5 5-5 4-6 5-6 



14 

 11 

 13 



4 

 20 

 27 

 14 



9 

 14 



2 

 U 



6 

 17 



7 

 12 



180 

 47.4 





 2 

 1 



i 

 1 



13 



1 



2 



46 

 12.1 



28 



20 



18 



5 



21 



23 



11 



4 



4 



1 



6 



2 



4 



2 



2 



151 

 39.7 



1 

 03 



2 

 0.5 



Average 



num. of 



toes per 



bird. 



9.3 

 9.3 

 9.1 

 9.1 

 9.0 

 8.9 

 8.9 

 8.7 

 8.7 

 8.7 

 8.7 

 8.6 

 8.6 

 8.5 

 8.4 



8.92 



B. SILKIE CROSSES (FiXFi). 



Serial 

 No 



16 

 17 

 18 

 19 

 20 

 21 

 22 

 23 

 24 



Pen 

 No. 



753 

 753 

 763 

 709 

 709 

 821 

 821 

 821 



Mother. 



No. 



2071 

 1966 

 2575 

 3827 

 1963 

 7413 

 7423 

 7428 



821 7408 



Races. 



Min.XSilk 



....Do.... 



....Do.,.. 



Silk. X Span 



....Do.. 



Silk.XCoch 



....Do.... 



....Do.... 



....Do.... 



No. 



of 



toes. 



4-4 

 4-4 

 4-5 

 4-4 

 4-4 

 5-5 

 5-5 

 6-6 

 6-6 



Father. 



No. 



2573 

 2573 

 2673 

 1578 

 1578 

 6096 

 6096 

 6096 

 6096 



Races. 



Min.XSilk.. 



....Do 



....Do 



Silk. X Span. 



....Do 



Silk.XCoch. 



....Do 



....Do 



....Do 



No. 



of 



toes. 



4-5 

 4-5 

 4-5 

 6-5 

 6-5 

 5-5 

 5-5 

 5-5 

 6-5 



Total (208). 



Offspring (Fs). 



Types of toes. 



64 



sd. d'd' d'd. dd. st. d't'. dt'. dt. ft', t't. tt 



102 



* Includes 1 case of 3-4 toes. 



Comparing tables 10 and 11, it is at once clear that in the second 

 hybrid generation the proportion of extra-toed offspring has decreased. 

 This accords with expectation, if extra-toe is dominant, for then only 75 

 per cent would be of the dominant type in F^, while 100 per cent would be 

 of that type in F,. 



