There has been much thought in the scientific community about the polymorphism of human blood types and their genetic factors, and disagreement and uncertainty about details like which evolutionary mechanism blood types have followed over the course of their development and how one’s blood type and environment interact. Investigation and study of blood types has revealed many aspects in which certain blood types provide some advantage to their possessors, providing evidence that they were beneficial and perhaps essential to some groups in the past, and that they might have implications on the health and survival of certain human populations today and in the future. There is extensive evidence supporting the hypothesis that blood types are long-lived
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Humans and their extinct relatives, Neandertals, both possess the same mutation that causes a null allele at the blood group gene, giving individuals the O blood type phenotype, and the allele’s frequency in both humans and sampled Neandertals suggests that the allele confers some advantage to its possessor and underwent positive selection in the common ancestor of both species (Lalueza-Fox et al. 2008). Focusing more on the human lineage, other alleles resulting in the O blood type emerged at least three times in the course of human evolution and were found to have changed over time due to recombination and selection, providing evidence that neutral evolution was not the factor that increased the frequency of blood group alleles and blood types (Calafell et al. 2008). The hypothesis that balancing selection has occurred on the blood group gene resulting in the maintenance of multiple alleles in the world’s human population is supported by studies on their effects on individuals in different populations. There is evidence that blood group antigens affect susceptibility to infectious diseases, as some blood types are much more frequent in areas rich in certain pathogens than others, which would explain why no one blood type allele has reached fixation (Fumagalli et al. 2009). Furthermore, it has been found that
Humans and their extinct relatives, Neandertals, both possess the same mutation that causes a null allele at the blood group gene, giving individuals the O blood type phenotype, and the allele’s frequency in both humans and sampled Neandertals suggests that the allele confers some advantage to its possessor and underwent positive selection in the common ancestor of both species (Lalueza-Fox et al. 2008). Focusing more on the human lineage, other alleles resulting in the O blood type emerged at least three times in the course of human evolution and were found to have changed over time due to recombination and selection, providing evidence that neutral evolution was not the factor that increased the frequency of blood group alleles and blood types (Calafell et al. 2008). The hypothesis that balancing selection has occurred on the blood group gene resulting in the maintenance of multiple alleles in the world’s human population is supported by studies on their effects on individuals in different populations. There is evidence that blood group antigens affect susceptibility to infectious diseases, as some blood types are much more frequent in areas rich in certain pathogens than others, which would explain why no one blood type allele has reached fixation (Fumagalli et al. 2009). Furthermore, it has been found that