[4] In December 2004, a paper titled CYP3A Variation and the Evolution of Salt-Sensitivity Variants was published which drew attention to the importance of the CPY3A5*1 and CPY3A5*3 alleles of cytochrome P450 CYP3A5 in hypertensive disease.
[5] The paper showed a substantial correlation between geographical latitude and the CPY3A5 allele distribution, with African Americans descended from the slave trade having retained the equatorial haplotype.
The paper shows that Black Americans having descended from the slave trade have largely retained the allele associated with equatorial populations, have higher sodium retention than other populations in America (including black people who later emigrated to America after the slave trade had ended), and have correspondingly higher hypertensive disease.
[8][10] Detractors argue that the hypothesis is inconsistent with historical evidence regarding salt deficiency in Africa or the causes of death aboard slave ships.
[11] Grim and Robinson responded to Kaufman and Hall, maintaining the validity of the hypothesis and its consistency with historical descriptions of slavery.