BLOODGROUPS AND INBREEDING 



439 



of people settling with an extreme low percentage of B might still manifest 

 this phenomenon now-a-days. Theoretically it is even possible that com- 

 plete extinction of the few carriers of group B finally gives rise to a popula- 

 tion where only group A and group are found. On the other side, selec- 

 tion might also go into the opposite direction and by frequent marriages of 

 group B with mutually it would be possible to surpass neighbouring places 

 as to the percentage of B. Still another possibility is the immigration of a 



399 334 



Avereest Markelo 



Staphorsi 



Vol I en hove 



Fig. 3 



547 469 



Puttershoek Surroundings 

 of Puttershoek 



Fig. 4 



foreigner belonging to group B in a farther inbreeding population nearly 

 lacking B. In one case we have been able to trace such an immigrant, who 

 had brought two centuries ago this hereditary biochemical trait of the blood 

 into a village, spreading it in all directions on the following generations. 



It is interesting to consider from these points of view the following col- 

 umns representing the different distribution of bloodgroups in quite neigh- 

 bouring rural places. We are wont to consider a high percentage of group 



