Carriers under extreme de-oxygenated conditions will exhibit similar characteristics to persons homozygous for the sickle cell anemia allele. Usually the HbS hemoglobin traits are not expressed enough to cause the carriers harm, but actually give a small protection to the carrier against malaria. The first mutation of the b -globin gene is thought to be in the African area around 1000BC to 1000AD (Edelstein, 1986). From the point at which the first mutation evolved some part of the mutation had to confer some type of advantage to the carrier. This adaptive advantage allowed more of the offspring to survive to propagate, and gradually to create a balance between the new mutant and the old b -globin. Sickle cell trait does give some advantage as a child being afflicted with malaria, but only if the child is heterozygous for the mutation. Homozygous individuals are afflicted with sickling cells, enlargement of the spleen, liver damage and the tendency to die young. Only fifty percent of individuals with sickle cell anemia disease will live to adult hood today.
This trait does not seem pleasant today, but for some tribes in Africa the trait is socially selected for and part of their society. In the Igbo tribes (having a 25% of the tribe as sickle cell carriers) it is thought that the malformations, such as the bossed skull, that sometimes come with the sickle cell anemia trait and disease are beautiful or that they confer some association with the spirits of the dead (such as shortened fingers or toes ). Even those not afflicted with the trait tend to cut off fingers or mutilate their children in some way to be more "protected" from the early death that a previous child has suffered. Some of the same mutilations are characteristic of the sickle cell disease and children already born with them are called "obanje" by the Igbo tribe (translated as "children who come and go"). The "obanje" are considered special and may be mutilated further with the notching of the ears or the cutting of one of their fingers to protect them from being taken away early or from returning to become another "obanje". This characteristic of the "obanje" is not localized to one tribe, but is seen in many tribes with a similarly high population percentage of sickle cell carriers. Evidence even suggests that perhaps this trait of missing or amputated fingers has been going on from the prehistoric ages.
Another correlation between social habits and sickle cell anemia is some tribes eating habits. In 1983 Durham found a "strong correlation" between the high percentage of carriers in certain populations and the consumption of yams. This correlation is only valid when one takes into account the rainfall in the areas examined. It has been hypothesized that yams might give the sickle cell disease suffers an advantage to live longer than normal and thus propagate due to a hemoglobin influencing property in the yams. The influence this would have in the population would to increase the amount of sickle cell carriers in the population. Without looking at the rainfall correlation against yam consumption this would not fit with the known facts about sickle cell anemia because it is the exact properties of sickle cell anemia that give the population a resistance against malaria and thus the worth to the sickle cell anemic trait. When one looks at the rainfall correlation with yam consumption one can observe that the tribes consuming the great amount of yams and with the highest sickle cell trait actually have a cession of yam consumption before the peak rain season and peak mosquito season. This correlation could mean that before the mosquito peak the tribes have observed tradition in not eating yams, but have also allowed their blood to come back to normal to protect them from malaria. After the highest rainfall times a festival for the first yam consumption after the rains is held, thus starting the cycle of the year over and giving the sickle cell anemic carriers a more level evolutionary ground again. (Edelstein, 1986)
These are social aspects of sickle cell anemia in the Old World, the disease in malaria-infested areas, but what about American society? In the early eighties about $100,000 was raised for sickle cell anemia compared with the millions raised for other diseases such as cystic fibrosis and muscular dystrophy. This discrepancy in funding has perhaps set back the scientific community. The knowledge we have about sickle cell anemia allows for many types of advancement in our genetic tools and the ability to fully understand a genetic disease from the onset. Along with the understanding of a disease from the onset sickle cell anemia is related to many other genetic blood diseases such as thalassimia and this relation can aid in the treatments of the other diseases along with sickle cell anemia.