Nucleotide sequence evidence of the unicentric origin of the beta C mutation in Africa.
The origin of the beta C mutation was studied by characterizing nucleotide sequence polymorphisms on beta C chromosomes of patients from various African countries. In the majority of cases, the beta C mutation was found in linkage disequilibrium with a single chromosomal structure as defined by classical RFLP haplotypes, intergenic nucleotide sequence polymorphisms immediately upstream of the beta-globin gene, and intragenic beta-globin gene polymorphisms (frameworks). In addition, three atypical variant chromosomes carrying the beta C mutation were observed, and are most probably explained either by a meiotic recombination (two cases) or by one nucleotide substitution occurring in an unstable array of tandemly repeated sequences (one case). These data demonstrate the unicentric origin of the beta C mutation in central West Africa, with subsequent mutational modification in a small number of instances. The data also supports gene flow of the beta C chromosome from subsaharan Africa to North Africa.
Centre de Génétique Moléculaire et Cellulaire, CNRS UMR 106, Université Claude Bernard Lyon I, Villeurbanne, France.
G
G
Trabuchet
J
J
Elion
O
O
Dunda
C
C
Lapouméroulie
R
R
Ducrocq
S
S
Nadifi
I
I
Zohoun
A
A
Chaventre
P
P
Carnevale
R L
RL
Nagel
D000349:Africa; D001483:Base Sequence; D004247:DNA; D005914:Globins / Q000235:genetics*; D006239:Haplotypes; D006801:Humans; D008969:Molecular Sequence Data; D009154:Mutation; D012150:Polymorphism, Restriction Fragment Length; D012091:Repetitive Sequences, Nucleic Acid
D005914:Globins; D004247:DNA