However, suggestions that smallpox selects against A, thereby explaining the high frequency of group A in Europe, and that the low frequency of O in ancient plague centers in Mongolia and the Middle East is also a reflection of selection are not supported by adequate data (Vogel et al, cited in Mourant et al 2(p18) Kreiger and Morton 24). 13 A similar hypothesis could explain the function of A and B antigens on vWF. 12 It is proposed that mutations like factor V Leiden lower the risk of hemorrhage and/or severe infections and thereby the risk of death during pregnancy. Such an argument has been made for the occurrence of the prothrombotic mutations factor V Leiden and prothrombin 20210G>A, which are commonly found in white humans dated as occurring 20 000 to 24 000 years ago toward the end of the last ice age. 11 These observations raise the possibility that a greater propensity for blood clot formation in non-O patients conferred a survival advantage to early humans. 9 A, B, and H blood group antigens are expressed on N-glycans of vWF and influence the half-life of the protein (10 hours for group O and 25 hours for non-O subjects), providing an explanation for the greater levels in non-O patients. 8, 10 The risk of VTE is probably related to the level of vWF and factor VIII because patients of group A2 have lower levels of these proteins than A1, B, and AB and have a lower risk of VTE. 8, 9 Non–group O patients have a greater risk of VTE than patients of group O and have greater levels of von Willebrand factor (vWF) and factor VIII. One of the most significant disease associations described for non-O (subjects of group A, B, or AB) versus O subjects is susceptibility to arterial and venous thromboembolism (VTE). Founder effects provide a more convincing explanation for the distribution of the D− phenotype and the occurrence of hemolytic disease of the fetus and newborn in Europe and Central Asia. Red cells lacking or having altered forms of blood group-active molecules are commonly found in regions of the world in which malaria is endemic, notably the Fy(a−b−) phenotype and the S-s− phenotype in Africa and the Ge− and SAO phenotypes in South East Asia. However, available evidence suggests surviving malaria is the most significant selective force affecting the expression of blood groups. There are clear examples of protection against infectious diseases from inheritance of polymorphisms in genes encoding and regulating the expression of ABH and Lewis antigens in bodily secretions particularly in respect of Helicobacter pylori, norovirus, and cholera infections. Advances in our understanding of the migration patterns of early humans from Africa to populate the rest of the world obtained through the use of Y chromosome and mtDNA markers do much to inform this debate. But is all of this enough to conclude that the Martian, Venusian, or other alien theories are correct? Perhaps a more important question to ask yourself is what will-or what should-happen if one of the theories is true.The relative contribution of founder effects and natural selection to the observed distribution of human blood groups has been debated since blood group frequencies were shown to differ between populations almost a century ago. More intriguing yet are claims that the physical, mental, and emotional awareness of these individuals is heightened-and no, this is not a sneaky lead into an upcoming movie or any sort of promotion whatsoever! In fact, it is widely known that pregnant women with type RH negative blood have extreme difficulty giving birth when their babies possess RH positive blood type in this situation, it is not a stretch to say the woman’s body actually attempts to kill the baby inside of it. Even more fascinating are the facts that these people tend to have green or blue eyes, naturally orange-colored hair, cool body temperatures, and sensitivity to hot temperatures. Furthermore, the vast majority of these latter individuals happen to reside in northern Europe. Oddly enough, RH negative blood can be utilized by any human being in need of a transfusion, but people with RH negative naturally coursing through their veins cannot make use of any other type of blood at all. Only 15% of human beings have this strange type of blood, and what’s more, these individuals have been described as having strange personal characteristics as well. But is it likely that RH negative blood has unearthly origins? Is it possible that human beings possessing the latter blood type are actually from Mars, Venus, or elsewhere in the universe? Well, since the known laws of physics breakdown past the horizons of black holes, truly anything is possible. All human blood types contain and are categorized by amounts of protein-except type RH negative, that is.
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