Nagel R L, Rao S K, Dunda-Belkhodja O, Connolly M M, Fabry M E, Georges A, Krishnamoorthy R, Labie D
Blood. 1987 Apr;69(4):1026-30.
Previous work has demonstrated that the HbS gene has appeared and expanded three times in Africa in three separate geographic locations and that these three distinct mutational events can be identified by linked DNA polymorphic sites (haplotypes) surrounding the abnormal gene. We have reported that the Senegalese and Beninian haplotypes differ in G gamma expression, mean percentage of HbF, and percentage of dense cells. We now report on the third haplotype, the Bantu, and find that it has intermediate features, namely, the high mean percentage of HbF and low percentage of dense cells associated with the Senegalese haplotype, but with a low percentage of G gamma expression similar to the Beninian haplotype. The distribution of percent HbF is quite different from Senegal haplotype-bearing sickle cell anemia patients since it covers a much wider range. The low G gamma expression is also different from the Beninians since it contains a significant and unique cluster of individuals with lower than 38% G gamma. Interestingly, among the Bantu there is a strong correlation between HbF levels and G gamma expression, which is not seen with the other haplotypes. These findings open the possibility that among the Bantu haplotype-bearing individuals two chromosomal types exist that define different levels of G gamma and HbF expression. Further structural exploration of these two potential subhaplotypes is needed.
先前的研究表明，HbS基因在非洲的三个不同地理位置出现并扩展了三次，这三次不同的突变事件可通过异常基因周围的连锁DNA多态性位点（单倍型）来识别。我们曾报道，塞内加尔和贝宁的单倍型在Gγ表达、HbF平均百分比和致密细胞百分比方面存在差异。我们现在报告第三种单倍型——班图单倍型，发现它具有中间特征，即与塞内加尔单倍型相关的高HbF平均百分比和低致密细胞百分比，但Gγ表达百分比低，类似于贝宁单倍型。HbF百分比的分布与携带塞内加尔单倍型的镰状细胞贫血患者有很大不同，因为其范围更广。低Gγ表达也与贝宁人不同，因为它包含一个显著且独特的个体群，其Gγ低于38%。有趣的是，在班图人中，HbF水平与Gγ表达之间存在很强的相关性，而其他单倍型则没有这种情况。这些发现表明，在携带班图单倍型的个体中，可能存在两种染色体类型，它们定义了不同水平的Gγ和HbF表达。需要对这两种潜在的亚单倍型进行进一步的结构探索。
