Section 15 — Human Genetics 



tained from unrelated individuals, have been 

 examined. The chemical findings previously re- 

 ported^) have been confirmed. Hemoglobin 

 Lepore appears to be made up of two normal a 

 peptide chains and of two abnormal peptide 

 chains (designated Lepore chains), resulting 

 from the fusion of part of the (3 peptide chain 

 with part of the 5 peptide chain. 



A method has been devised to analyze by 

 fingerprinting the trypsin-resistant "core" of the 

 Lepore chain. More information on the chemical 

 structure of the Lepore chain has been obtained 

 by this method of analysis. The region where 

 the 5 chain-like portion of the Lepore chain 

 is joined to the (3 chain-like portion has been 

 localized in the "core". This region is comprised 

 between residue 85 and residue 115 of the Le- 

 pore peptide chain. When digested by trypsin, 

 this chain yields peptides identical to either (3 or 6 

 chain peptides. The entire Lepore chain can 

 now be accounted for; it appears to have the 

 same length as the (3 and 5 chains. These 

 chemical findings suggest that a very specific 

 genetic event is responsible for the formation 

 of the Lepore chain. The fusion of complemen- 

 tary regions of these peptide chains is most likely 

 caused by a non-homologous crossing-over 

 between corresponding points of the |3 and 5 

 genes. 



1. C. Baglioni, Proc. Nat. Acad. Sc. 

 48(1962) 1880. 



15.76. Serological Recent Data for the Gm Groups. 

 Their Interest in Sero-anthropology. C. Ro- 

 partz, L. RiVATand P.-Y. Rousseau (Rouen, 

 France). 



As soon as 1961 we assumed that the Gm(b) 

 factor had not an elementary structure. It is 

 but very recently that such a phenomenon has 

 been highly proved. 



Whereas Steinberg found one anti-Gm(b) 

 specific to the whites, we demonstrated that 

 what was called Gm(b) in the yellow Races was 

 in reality a mosaic of numerous unities, specially 

 among the Japanese : sera, specific for the Gm(b) 

 factor in the white people, define 3 different 

 structures among Japanese. 



These facts, if complicating the immunolo- 

 gical study and the analysis of the genetical 

 determinism, give the gamma-globulins system 

 "Gm" a capital importance in sero-anthropology 

 and human genetics. 



In fact, specific anti-Gm(b) reagents have 



already helped us to review the cross-breeding 

 percentage of the US Negroes. Moreover deep 

 qualitative and quantitative differences in the 

 expression of the mosaic Gm(b) among yellow 

 races highly contribute to study the problem of 

 their paleo-migrations and cross-breeding. So, 

 the Chinese of Macao considerably differ from 

 the Japanese, and important variations are 

 found between different tribes of Central and 

 North American Indians. 



Although the genetical determinism of that 

 mosaic which constitutes the Gm(b) factor is 

 still unknown, it is beyond doubt that the 

 facts that we present will help to its study. 



Indeed, mind is not satisfied when obliged to 

 accept the presence of the same gene: Gm ab , 

 which should be omnipresent in the melanoder- 

 ma populations, only very frequent in the xan- 

 thoderma ones. 



15.77. Studies on the Hereditary Gamma Globulin 

 Factors: Their Relation to Immune Tolerance 

 and Studies on the Antibodies to the Hereditary 

 Gamma Globulin Factors in Man and their Rela- 

 tion to Immune Tolerance. Arthur G. Stein- 

 berg and Janet A. Wilson (Cleveland, 

 U.S.A.). 



The hereditary gamma globulin factors (Gm 

 and Inv) are detected by means of an agglutina- 

 tion inhibition test. The antibodies which detect 

 these factors may be formed as a result of trans- 

 fusions of whole blood, injection of gamma glo- 

 bulin, or immunization of the infant by the 

 transplacental "transfusion" of the mother's 

 gamma globulin. It is of interest that the mother's 

 gamma globulin does not induce immune toler- 

 ance even though it is present in high concen- 

 tration before and after birth. 



The antibodies are usually carried by (32 M 

 molecules but they may also occur on 7sy- 

 globulin molecules. The latter may cross the 

 placenta and be found in the infant. The anti- 

 bodies may be induced in rhesus monkeys, 

 but it is not yet clear that these are identical 

 with those formed in humans. 



The antigens do not appear to cause trans- 

 fusion reactions when given to recipients who 

 have antibodies to them. 



Data collected in this and other laboratories 

 will be presented to substantiate the above 

 statements. 



295 



