Bias also means that little is known about how variations elsewhere in the genome modify conditions.With sickle-cell disease, red blood cells look like bananas rather than, as is normal, round cushions.About 75% of the 300,000 babies born every year with sickle-cell disease are African.The high share reflects a bittersweet twist in the evolutionary tale;sickle-cell genes can confer a degree of protection against malaria.Other mutations are known to lessen sickle-cell’s impact,but most knowledge of genetic modifiers is particular to Europeans.Quicker and more accurate diagnosis would mean better treatment.The sooner parents know their children are deaf, the sooner they can begin sign language.Algorithms that incorporate genetic information, such as one for measuring doses of warfarin, a blood-thinner, are often inappropriately calibrated for Africans.Knowing more about Africans’ genomes will benefit the whole world.The continent’s genetic diversity makes it easier to find rare causes of common diseases.Last year researchers investigating schizophrenia sequenced the genomes of about 900 Xhosas (a South African ethnic group) with the psychiatric disorder.They found some of the same mutations that a team had discovered in Swedes four years earlier.
