HUMAN GENETICS 343 



among them, the majority belonging to group O. In all other popula- 

 tions both A and B are present, though the proportions vary somewhat 

 and these variations may be correlated with other genotypic differences. 

 Thus Hungarian gipsies show a gene ratio more Hke that of Indians, 

 from whom they are probably descended, than that of the Hungarian 

 population by which they are surrounded. Bernstein^ has suggested that 

 primitively the human race contained neither A nor By and that A 

 arose in Europe, B in East Asia, both genes having since spread from 

 their place of origin. But the evidence is not very convincing, ar.d as 

 homologous genes exist in the higher apes, it is perhaps unhkely that 

 they have arisen anew in man. 



Some of the rare pathological genes are more common in some racial 

 groups than in others, e.g. family amaurotic idiocy (recessive?) occurs 

 more frequently in Jews. But a recent investigation showed that most 

 such genes have a very similar incidence in Japanese and Europeans." 

 There may also be differences between the major racial groups in the 

 frequency of the extremely important genes determining susceptibility 

 or resistance to diseases. Negroes are usually much more susceptible to 

 tuberculosis than whites and less so to malaria and various parasites. 

 Also the commonest sites of incidence for cancer are different in 

 different races, even when the total rate of incidence is the same; but 

 within the same racial group the total incidence of cancer may be the 

 same in men and women, but usually the disease attacks the genital 

 tract of the latter and some other organ system of the former.^ Our 

 exact knowledge of disease resistance is, however, very incomplete and 

 in many cases we do not even know for certain that it is genetically 

 determined. 



3. Nations and Races 



The concept of nationality has, in recent years, often been confused 

 with that of race. It should be unnecessary to state that nationality 

 is not a genetical concept at all. It can be defined either in political 

 terms, as all the people living under a certain government, or in cultural 

 terms, as all the people enjoying a certain cultural tradition. Neither of 

 these entities has anything to do with the concept of race, even on the 

 loosest definition of that troublesome word. The habit of referring to 

 alleged national characteristics, such as "British hypocrisy" or sense of 

 "cricket," as though they were racially determined, is also clearly 



^ Bernstein 1931. ^ Komai 1934. ^ Kennaway and Kennaway 1937. 



