Is sickle cell an indicator of black ancestry?
Yes. If the scientific consensus that the sickle cell strains present in Sicily and many other parts of Southern Europe originated in sub-Saharan Africa is correct, then in these cases, sickle cell is unambiguous proof of Negroid ancestry. Period. If a gene originated in Negroids, and you have it, then you have at least one Negroid ancestor. There is no other explanation.
J Med Genet 1980 Feb;17(1):34-8
Roth EF Jr, Schiliro G, Russo A, Musumeci S, Rachmilewitz E, Neske V, Nagel R.
The chemical and physical properties of haemoglobin S derived from homozygotes for this haemoglobin in Sicily were examined, as well as some erythrocytic characteristics. Sicilian Hb S was identical to that found in USA black patients in electrophoretic mobility on both starch and citrate agar media, solubility, mechanical precipitation rate of oxyhaemoglobins, and minimum gelling concentration, as well as by peptide mapping and amino-acid analysis of all beta-chain peptides. Taken together with the presence in Sicily of African blood group markers and certain historical considerations, it seems clear that the source of Hb S in Sicily is Africa. While the clinical severity in nine Sicilian children did not seem remarkably different from the disease in the USA, the most severe and fatal complications were not seen. Mean Hb F Was 10.5% and 2,3-diphosphoglycerate (2,3-DPG) values were higher in Sicilian homozygotes than in black USA counterparts (21.79 mumol/g Hb vs 15.16). Red cell AT values were also slightly higher in Sicilian patients. The presence of concomitant thalassaemia was excluded by both family studies and globin chain synthetic ratios. In conclusion, haemoglobin S in Sicilian homozygotes is identical to Hb S found in USA blacks. Although the severity of the disease seems quite similar in both groups of patients, other erythrocytic properties were found to be different. Whether these factors influence severity remains to be elucidated.
PMID: 7365760 [PubMed - indexed for MEDLINE]
Acta Haematol 1978;60(6):350-7
Sandler SG, Schiliro G, Russo A, Musumeci S, Rachmilewitz EA.
As an approach to investigating the origin of sickle cell hemoglobin (hemoglobin S) in white persons of Sicilian ancestry, two groups of native Sicilians were tested for blood group evidence of African admixture. Among 100 unrelated Sicilians, the phenotypes cDe(Rho) and Fy(a-b-), and the antigens V(hrv) and Jsa, which are considered to be African genetic markers, were detected in 12 individuals. Among 64 individuals from 21 families with at least one known hemoglobin S carrier, African blood group markers were detected in 7 (11%). These findings indicate that hemoglobin S is only one of multiple African genes present in contemporary Sicilian populations. The occurrence of hemoglobin S in white persons of Sicilian ancestry is considered to be a manifestation of the continuing dissemination of the original African mutation.
PMID: 103355 [PubMed - indexed for MEDLINE]
The sickle cell mutation in Southern Europe had its origins in sub-Saharan Africa.
The Benin haplotype accounts for HbS associated chromosomes in Sicily, Northern Greece, Southern Turkey, and South West Saudi Arabia, suggesting that these genes had their origin in West Africa.
RM acknowledges this fact on his page, but somehow misses its significance.
It makes no difference whether the gene was brought to Southern Europe by Negroids or North African Caucasoids. The end result -- irrefutable black ancestry -- is the same.
It is true that sickle cell, being subject to selection, is not a good marker for determining the actual amount of Negroid ancestry. But the bulk of evidence says it definitely is, to quote RM's "myth", "an indicator of black ancestry". While non-existent "Hamito-Semitic" ancestry is enough to prove Northern Europeans are not "pure", to RM's mind Southern Europeans somehow remain "pure" since their Negroid genes were "laundered" through North Africans. Hilarious.
So, to recap:
(a) Sickle cell in Southern Europeans is absolute, unambiguous proof of Negro ancestry. Moreover, it is Negroid admixture that is likely to manifest itself phenotypically.
(b) Since it has been selected for by the environment, the sickle cell trait is not an ideal marker for determining precise levels of Negroid admixture. Nor, of course, is it proof that Negroes once roamed around on Sicily.
Since I'm at least making an attempt at balance here, I'll also show you the following study; in which Negroid admixture was found in Sicilians, but "at a much lower level than previously thought".
Am J Hematol 1992 Aug;40(4):313-5
Ragusa A, Frontini V, Lombardo M, Amata S, Lombardo T, Labie D, Krishnamoorthy R, Nagel RL.
I.R.C.C.S., OASI, Troina, Italy.
African admixture in Sicily has been long suspected because of the presence of the sickle gene. Nevertheless, the degree of African admixture cannot be derived from the study of HbS frequency, since this gene was most likely expanded by the selective pressure of malaria, for a long time endemic to the region. We have examined 142 individuals from the Sicilian town of Butera (12% sickle trait) to search for other markers of the globin gene cluster less likely to be selected for by malaria. The TaqI polymorphism in the intervening sequences between the two gamma genes is informative. We have found only two instances of this African marker (TaqI(-)) among 267 normal chromosomes, demonstrating that the admixture occurred at a much lower level than previously thought.
PMID: 1503087 [PubMed - indexed for MEDLINE]
If RM were reasonable, he would have mentioned that sickle cell is subject to selection and that areas with sickle cell don't necessarily have higher levels of Negroid admixture than those without, and left it at that. Instead, he ridiculously argues that possessing a gene that originated in sub-Saharan Africans is not an indication of Negroid ancestry. Bottom line: if a Sicilian has HbS, he has Negroid ancestors from Benin. Besides HbS, the Negroid contribution could be small, maybe even undetectable in some cases. But it is present -- you don't carry a gene from Benin unless you have ancestry from Benin. "Evolution" can't magically make you carry a gene unless one of your parents carried it. And one of their parents carried it. And so on, until, at some point, one of someone's parents was a Negro.