Researchers have traced the emergence of the sickle cell variant to a single event that took place about 7,300 years ago, as GenomeWeb has reported.
Previous studies had indicated the presence of five sickle cell haplotypes, named after the regions were they are most common, and suggested different origins for the various haplotypes.
A pair of National Human Genome Research Institute researchers identified 156 sickle cell mutation carriers from within 2,932 individuals whose whole genomes were sequenced by the 1000 Genomes Project, the African Genome Variation Project, or a sequencing effort in Qatar. As they report in the American Journal of Human Genetics, Daniel Shriner and Charles Rotimi, both of NHGRI's Center for Research on Genomics and Global Health, classified the carriers into three main haplotypes based on 27 informative markers. The ancestral sickle allele, the researchers say, arose some 259 generations ago and then differentiated into the various haplotypes.
Rotimi tells the New York Times that knowing how the sickle cell variant arose could help answer other questions about the disease such as why it is more severe in certain people as well as lead to improvements in care. "It would definitely help physicians to treat patients at a global level," he says.