Section 15 — Human Genetic* 



dizygotic twinning rate has decreased significant- 

 ly during an observation period of 200 years 

 (similar results have also recently been observed 

 for Aland as a whole and in Sweden). 



Not only the inhabitants shown by the genea- 

 logical analysis to be of pure native descent 

 for at least 4 generations but also the population 

 as a whole, have some extreme blood groups 

 frequencies. The A-blood group percentages 

 67-70 (gene frequencies: pi = 0.27-0.28, P2 = 

 0.17-0.18) are to our knowledge the highest 

 hitherto reported for a white population. The 

 frequency of D-negative individuals is very 

 high. The frequencies of the following genes 

 are low: q in the ABO-system, M in the MN- 

 system, Hp 1 of the haptoglobin serum groups, 

 Gm x of the gamma globulin groups and Gc 1 of 

 the group specific components (Gc 1 = 0.615 is 

 the lowest yet recorded in the literature). 



Some hereditary diseases, such as recessive 

 autosomal tapetoretinal degeneration and the 

 Aland Islander bleeder syndrome (v. Wille- 

 brand's disease, Thrombopathia v. Willebrand- 

 Jurgens) have a noteworthy frequency. 



15.22. The Blood Groups of Ashkenazic Jews. 



F. Ottensooser, N. Leon, M. Sato and P. H. 

 Saldanha (Sao Paulo, Brazil). 



The genetical diversity of Jewish people and 

 the persistence of their communities as isolates 

 within other populations pose interesting evolu- 

 tionary problems. 



From 586 B.C. to modern times there have 

 been several Jewish dispersal movements which 

 resulted in four main Jewish groups: Ashkenazic 

 or Eastern European Jews, Sephardic or Medi- 

 terranean Jews, Oriental or Asiatic Jews and 

 Yemenite Jews. Before and during dispersal, 

 Jewish populations acquired various non- 

 Jewish components and gene flow into Jewish 

 communities appears to have been strong during 

 captivity in Egypt and in the Roman Empire. 



Several polymorphic traits have been studied 

 among Jewish populations of various origins 

 and blood groups proved to be especially useful 

 for comparing Jewish populations with their 

 neighbours. 



The ABO, MN and Diego blood groups of 

 100 Ashkenazic Jews in Sao Paulo, Brazil were 

 investigated. All subjects were Diego-negative. 

 The ABO and MN frequencies were similar to 

 those in previous Askhenazic samples. Rh fre- 

 quencies presented typical Mediterranean dis- 

 tributions, Ashkenazic Jews showing higher B 

 and R° gene frequencies and lower r frequency 

 than their neighbours. Probably these characteris- 



tics were inherited from ancient Hebrews in 

 Palestine. 



The high B values of the Ashkenazim and their 

 low values of non-tasters and Rh negatives are 

 not derived from intermarriage with Mongo- 

 loid people but a Mediterranean heritage as 

 evidenced by absence of Diego-positives and 

 high R° values. The incidence of R° gene also 

 suggests that an African component similar to 

 that found today in Egyptians was present be- 

 fore the diaspora. The Jews that preserved a 

 small but constant Negro component during thou- 

 sands of years are an example of social isolate 

 comparable to endogamous groups in India. 



15.23. A Comparative Study on Blood Groups Dis- 

 tribution among Normal and G6PD Deficient 

 Subjects in Israel. A. Adam, L. Dressler, 

 C. Sheba and A. SzeInberg (Tel Hashomer, 

 Israel). 



A recent investigation demonstrated signifi- 

 cantly lowered frequency of the E gene (Rh 

 system) among glucose-6-phosphate dehydroge- 

 nase (G6PD) deficient American Negroes, as well 

 as a tendency toward differences in the B and O 

 blood groups distribution, between them and the 

 normal controls (*) 



In a similar study, carried out in Israel, about 

 a thousand normal and 350 G6PD deficient 

 subjects were tested simultaneously for G6PD 

 activity and for the distribution of the Rh and 

 ABO blood groups. The investigated popula- 

 tion included representative samples of several 

 communities (Jews from Kurdistan, Iraq, Iran 

 and Yemen and Israeli Arabs) in which G6PD 

 deficiency is frequent. 



No significant differences were detected be- 

 tween the distribution of the various Rh genes 

 among C6PD deficient and normal subjects in 

 each of the communities investigated. 



Similarly no deviations from homogeneity 

 was found in the ABO distribution except for the 

 Kurdish community. In this sample (102 nor- 

 mals and 112 G6PD deficients) a significantly 

 lower frequency of 0-group and higher frequency 

 of A group was found among the G6PD defi- 

 cients (P<02). 



A larger population sample is being studied 

 in order to examine the significance of this 

 observation. 



1. Tarlov, A. R., Brewer, G. J., Carson, 

 P. E. and Alving, A. S. Primaquine sensitivity, 

 Arch. Int. Med. 109, 209 (1962). 

 This investigation was supported by grants 



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