Genetic studies suggest a multicentric origin for Hb G-Coushatta [β22(B4)Glu→Ala]

J. Li, D. Wilson, M. Plonczynski, A. Harrell, C. B. Cook, W. D. Scheer, Y. T. Zeng, M. B. Coleman, M. H. Steinberg

Research output: Contribution to journalArticlepeer-review

8 Scopus citations


Hb G-Coushatta [β22(B4)Glu→Ala] is found in geographically separated ethnic groups. Commonest along the Silk Road region of China but also present in the North American Coushatta, we sought to determine whether this variant had a unicentric or multicentric origin. We examined the haplotype of the β- globin gene cluster in two Chinese families and in five Louisiana Coushatta heterozygous for this mutation. Chinese and Louisiana Coushatta had different haplotypes associated with the identical Hb G mutation. These haplotypes were defined by the presence of a HindIII restriction site in the (A)γ-globin gene and AvaII restriction site in the β-globin gene in Chinese subjects and their absence in the Louisiana Coushatta. We found a CAC at codon β2 (β- globin gene framework 1 or 2) linked to the Hb G-Coushatta gene in Chinese, and a CAT(framework 3) in Louisiana Coushatta, indicating different β- globin gene frameworks. Both the Hb G-Coushatta mutation (GAA→GCA) and the codon 2 CAC→CAT polymorphism are normal δ-globin gene sequences, suggesting the possibility of gene conversion. We conclude that Hb G-Coushatta had at least two independent origins. This could be due to separate mutations at codon β22 in Chinese and Louisiana Coushatta, a mutation at this codon and a β→δ conversion, or two β→δ gene conversion events.

Original languageEnglish (US)
Pages (from-to)57-67
Number of pages11
Issue number1
StatePublished - 1999


  • Abnormal hemoglobin (Hb)
  • Globin gene
  • Haplotype

ASJC Scopus subject areas

  • Hematology
  • Genetics(clinical)
  • Clinical Biochemistry
  • Biochemistry, medical


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