Blood groups in man / by R.R. Race and Ruth Sanger.

  • R.R. Race
Date:
1954
Catalogue details

Licence: Attribution-NonCommercial-NoDerivatives 4.0 International (CC BY-NC-ND 4.0)

Credit: Blood groups in man / by R.R. Race and Ruth Sanger. Source: Wellcome Collection.

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    The chromosomes CDe 0*580 and cDE 0*307 were commonest, the next in frequency being cde 0*08. The chromosome CDE was isolated but not cDe. The authors did not consider that their results conflicted with the crossing-over hypothesis. From the work of Wiener, Davidsohn and Potter, 31 of Levine, 32 and of Miller, Rosenfield and Vogel, 47 it is clear that in American negroes the order of gene frequency is cDe, cde, cDE and CDe. The only heterozygotes that could, at crossing-over, produce any fresh combinations are cDE/cde, CDe/cde and CDe/cDE. They would, according to the theory, produce cdE, Cde and CDE, all in lower frequencies than in Europeans. The authors quoted found cdEjcde and Cde I cde. So far no CDE has been identified and this is not surprising, for it could only disclose itself directly in the genotype CDe/CDE, and CDe has a frequency of only about o-io. Simmons and Graydon 33 tested 234 Australian aborigines. CDe 0-56 was the commonest chromosome, then cDE 0-20, then Cde 0-13. The heterozygote CDe/cDE would have a frequency of 0-22. According to the hypothesis the cross-over chromosomes would be CDE and cDe, and both of these were observed. Four out of the 234 samples gave the reaction Cde ¡Cde, and the authors rightly considered that these chromosomes could hardly have originated as cross-overs. It would be most interesting to know whether these four blood samples would have given a positive indirect anti globulin test with incomplete anti-D serum. It may be that the low grade of D u antigen is common in the aborigines. It has been suggested 34 that the chromosome CD u e arises not as a cross-over from CDe/cde but as a mutation in a CDe chromosome. Such blood samples would be expected to have their greatest frequency in a population where the chromosome CDe was frequent. That high grade D u was not responsible Simmons and Graydon made clear: the low grade D u was at that time only beginning to be recognized in England. No evidence of the existence of the chromosome Cde was found by Sanger, Walsh and Kay 42 in testing 178 Australian aborigines. In a later paper Walsh 43 demonstrated the presence in aborigines of the chromosome CD u e. Since the first edition of this book a very large amount of anthro pological data has been published and from which it is possible to pick results strikingly in favour of the crossing-over idea—and strikingly against it. Ottensooser and Pasqualin 44 criticized the idea at length: in testing Brazilian Indians of the Matto Grosso area they had found
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