8 AIASS. EXPERIMENT STATION BULLETIN Zll 



Breeding Behavior of Full Brothers and Sisters 



Nineteen groups of full brothers and sisters were tested to discover the 

 percentage of broodiness in their daughters for the first laying year. 

 These groups include 24 brothers and 26 sisters. A group is made up of 

 one brother and one or more of his sisters, or of more than one brother 

 and one or more of their full sisters. The mean percentage of broody 

 daughters based on the mean of families is recorded in table 4. 



Table 4. — Breeding Beh.wior of Full Brothers and Sisters. 



Group Percentage of Broody Daughters 



No.» ^ 



Brothers Sisters 



1 37.4 25.0 



2 50.0 20.8 



3 0.0 43.0 



4 14.2 10.0 



5 4.2 12.5 



6 50.0 40.0 



7 100.0 100.0 



8 18.0 20.0 



9 25.0 8.0 



10 18.0 25.3 



11 37.5 14.5 . 



12 5.0 20.0 



13 0.0 0.0 



14 7.6 12.5 



15 0.0 Z.-i 



16 0.0 0.0 



17 8.5 13.5 



18 0.0 0.0 



19 10.4 3.5 



Mean 20.31 19.57 



*A group is made up either of one brother and one or more 

 of his full sisters, or of more than one brother and one or more 



of their full sisters. The total number of brothers was :2 4 and of 

 sisters, 26. 



If there were a sex-linked factor and' one or more autosomal factors 

 concerned in the inheritance of broodiness, it being a dominant character, 

 brothers would be expected to transmit the character to a higher per- 

 centage of their daughters than would their sisters. 



The data in table 4 show that in seven of the groups broodiness was 

 transmitted to more daughters by the brothers, while in eight of the 

 groups the reverse was true, and in four groups the brothers and sisters 

 transmitted equally. Such breeding results would be anticipated on the 

 basis of autosomal factors by the law of chance, but not on the basis of 

 sex-linked factors. 



