Atypical haplotypes linked to the β<sup>s</sup> gene in Africa are likely to be the product of recombination

Srinivas, Rao; Dunda, Olga; Krishnamoorthy, Rajagopal; Fabry, Mary E.; Georges, A. J.; Labie, Dominique; Nagel, Ronald L.

doi:10.1002/ajh.2830290117

Cited by 35 publications

(30 citation statements)

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“…Benin is the most frequent with a frequency of 0.479, followed by Bantu (0.406), Senegal (0.031), and Saudi Arabia/Indian (0.021). The Bantu A2 and Bantu A7 atypical haplotypes described by Srinivas et al (1988) were observed with a frequency of 0.042 and 0.021, respectively. No Cameroon haplotypes were identified in this study.…”

Section: Resultsmentioning

confidence: 97%

“…The frequencies of the two atypical haplotypes, Bantu A2 (4.2%) and Bantu A7 (2.1%), are some of the highest reported in American populations. This observation can be interpreted as resulting from of recombinatorial events involving the Bantu typical haplotype and the 5' regions from various haplotypes present in normal individuals as described by Srinivas et al (1988). In an admixed population such as the Venezuelan, there are more probabilities of observing these events.…”

Section: Discussionmentioning

confidence: 99%

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Beta-globin gene cluster haplotypes in Venezuelan sickle cell patients from the State of Aragua

et al. 2002

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Seven polymorphic sites in the β-globin gene cluster were analyzed on a sample of 96 chromosomes of Venezuelan sickle cell patients from the State of Aragua. The Benin haplotype was predominant with a frequency of 0.479, followed by the Bantu haplotype (0.406); a minority of cases with other haplotypes was also identified: atypical Bantu A2 (0.042), Senegal (0.031), atypical Bantu A7 (0.021) and Saudi Arabia/Indian (0.021) haplotypes; however, the Cameroon haplotype was not identified in this study. Our results are in agreement with the historical records that establish Sudanese and Bantu origins for the African slaves brought into Venezuela.

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Section: Resultsmentioning

confidence: 97%

Section: Discussionmentioning

confidence: 99%

Beta-globin gene cluster haplotypes in Venezuelan sickle cell patients from the State of Aragua

et al. 2002

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“…Most of the cases from Brazil represent mutations or recombinations involving the Bantu ␤ S -gene; in two previous studies [7,8], the structure of the atypical haplotypes revealed recombinations only of the Bantu haplotype. This is probably due to the fact that all those studies were carried out in regions where the Bantu haplotype predominates: Angola, Mozambique, and Brazil [18,19].…”

Section: Discussionmentioning

confidence: 99%

“…Little attention has been paid to these atypical haplotypes. One study refers to them as variations of the Bantu haplotype whereas other reports consider them as the product of recombination of Bantu haplotypes [7][8][9].…”

Section: Introductionmentioning

confidence: 99%

Atypical ?s haplotypes are generated by diverse genetic mechanisms

et al. 2000

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The majority of the chromosomes with the ␤ S gene have one of the five common haplotypes, designated as Benin, Bantu, Senegal, Cameroon, and Arab-Indian haplotypes. However, in every large series of sickle cell patients, 5-10% of the chromosomes have less common haplotypes, usually referred to as "atypical" haplotypes. In order to explore the genetic mechanisms that could generate these atypical haplotypes, we extended our analysis to other rarely studied polymorphic markers of the ␤ S -gene cluster, in a total of 40 chromosomes with uncommon haplotypes from Brazil and Cameroon. The following polymorphisms were examined: seven restriction site polymorphisms of the ␥␦␤-cluster, the pre-G ␥ framework sequence including the 6-bp deletion/insertion pattern, HS-2 LCR (AT)xR(AT)y and pre-␤ (AT)xTy repeat motifs, the GC/TT polymorphism at −1105-1106 of G ␥-globin gene, the C/T polymorphism at −551 of the ␤-globin gene, and the intragenic ␤-globin gene framework. Among the Brazilian subjects, the most common atypical structure (7/16) was a Bantu 3-subhaplotype associated with different 5-sequences, while in two chromosomes a Benin 3-subhaplotype was associated with two different 5-subhaplotypes. A hybrid Benin/Bantu configuration was also observed. In three chromosomes, the atypical haplotype differed from the typical one by the change of a single restriction site. In 2/134 chromosomes identified as having a typical Bantu RFLPhaplotype, a discrepant LCR repeat sequence was observed, probably owing to a crossover 5 to the -gene. Among 80 ␤ S chromosomes from Cameroon, 22 were associated with an atypical haplotype. The most common structure was represented by a Benin haplotype (from the LCR to the ␤-gene) with a non-Benin segment 3 to the ␤-globin gene. In two cases a Bantu LCR was associated with a Benin haplotype and a non-Benin segment 3 to the ␤-globin gene. In three other cases, a more complex structure was observed that can be considered as a hybrid of Benin, Bantu, Senegal, or other chromosomes was observed. These data suggest that the atypical ␤ S haplotypes are not uncommon in America and in Africa. These haplotypes are probably generated by a variety of genetic mechanisms including (a) isolated nucleotide changes in one of the polymorphic restriction sites, (b) simple and double crossovers between two typical ␤ S haplotypes or much more frequently between a typical ␤ S haplotype and a different ␤ Aassociated haplotype that was present in the population, and (c) gene conversions. Am.

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“…The frequency of the atypical haplotype Bantu A2 (20%) is the highest reported in American populations so far. This haplotype may arise as the result of recombination events between the 5' regions of the Bantu typical haplotype and other haplotypes present in b A chromosomes (Srinivas et al, 1988). However, this figure may be overestimated due to the small number of chromosomes analyzed.…”

Section: Discussionmentioning

confidence: 91%

alpha-thalassemia, HbS, and beta-globin gene cluster haplotypes in two Afro-Uruguayan sub-populations from northern and southern Uruguay

et al. 2006

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Hemoglobinopathies are the most common monogenic disorders worldwide; however, they have never been systematically studied from a genetic perspective in Uruguay. In this study, we determined the frequencies of hemoglobin variants in Afro-Uruguayans. A sample of 52 healthy unrelated Afro-Uruguayans from the northern (N = 28) and southern (N = 24) regions of the country was analyzed. Eight individuals (15.4%) were heterozygous for -a 3,7 thalassemia; seven of them (29.2%) were originally from the southern region, whereas one of them (3.6%) was from the northern region; the differences between both regions were statistically significant (p = 0.016 +/-0.003). The only structural mutation detected was b S , which is typical of African populations. Four individuals (10%) were heterozygous for b S , three of them (13.6%) from the South, and one (5.6%) from the North. The b S haplotypes were analyzed in eight individuals: two were homozygous b S /b S , two were heterozygous b S /b thal , and four were heterozygous b S /b A . This haplotype distribution (60% Bantu, 20% Benin, and 20% Bantu A2) is in agreement with historical records reporting a predominantly Bantu origin for the enslaved Africans brought to Uruguay. Even though this is a preliminary study, due to the small sample size, our results are suggestive of a relatively high incidence of hemoglobinopathies in the Afro-Uruguayan population.

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Atypical haplotypes linked to the β^s gene in Africa are likely to be the product of recombination

Cited by 35 publications

References 6 publications

Beta-globin gene cluster haplotypes in Venezuelan sickle cell patients from the State of Aragua

Beta-globin gene cluster haplotypes in Venezuelan sickle cell patients from the State of Aragua

Atypical ?s haplotypes are generated by diverse genetic mechanisms

alpha-thalassemia, HbS, and beta-globin gene cluster haplotypes in two Afro-Uruguayan sub-populations from northern and southern Uruguay

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Atypical haplotypes linked to the βs gene in Africa are likely to be the product of recombination

Cited by 35 publications

References 6 publications

Beta-globin gene cluster haplotypes in Venezuelan sickle cell patients from the State of Aragua

Beta-globin gene cluster haplotypes in Venezuelan sickle cell patients from the State of Aragua

Atypical ?s haplotypes are generated by diverse genetic mechanisms

alpha-thalassemia, HbS, and beta-globin gene cluster haplotypes in two Afro-Uruguayan sub-populations from northern and southern Uruguay

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Atypical haplotypes linked to the β^s gene in Africa are likely to be the product of recombination