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Microsatellite markers reveal low levels of population sub-structuring of Plasmodium falciparum in southwestern Nigeria.

Oyebola MK, Idowu ET, Nyang H, Olukosi YA, Otubanjo OA, Nwakanma DC, Awolola ST, Amambua-Ngwa A - Malar. J. (2014)

Bottom Line: No matching multilocus haplotypes were found and analysis of multilocus LD showed no significant index of association.Genetic differentiation between populations was low (ΦPT = 0.017).The absence of detectable population structure of P. falciparum in southwestern Nigeria is evident in the lack of significant differentiation between populations separated by about 200 km.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Council, Gambia Unit, Fajara, The Gambia. angwa@mrc.gm.

ABSTRACT

Background: Genetic diversity studies provide evidence of Plasmodium falciparum differentiation that could affect fitness and adaptation to drugs and target antigens for vaccine development. This study describes the genetic structure of P. falciparum populations in urban and rural sites from southwestern Nigeria.

Methodology: Ten neutral microsatellite loci were genotyped in 196 P. falciparum infections from three localities: Aramoko-Ekiti, a rural community; Lekki, an urban location and Badagry, a peri-urban border settlement. Analysis was performed on the genetic diversity, linkage disequilibrium, population structure and inter-population differentiation.

Results: Allelic diversity values were similar across all populations, with mean expected heterozygosity (HE) values between 0.65 and 0.79. No matching multilocus haplotypes were found and analysis of multilocus LD showed no significant index of association. Genetic differentiation between populations was low (ΦPT = 0.017).

Conclusion: The absence of detectable population structure of P. falciparum in southwestern Nigeria is evident in the lack of significant differentiation between populations separated by about 200 km. This implies that a fairly uniform malaria control strategy may be effective over a wide geographic range in this highly endemic region. However, more wide-scale survey across the country will be required to inform malaria control in this large and densely populated endemic region.

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Related in: MedlinePlus

Frequency distribution of the allele lengths (bp) at 10 microsatellite loci in the threeP. falciparumpopulations. Allele sizes determined by capillary electrophoresis are shown on the x-axis and their frequencies on the y-axis. Vertical bars for each population represent allele frequencies of major alleles for each microsatellite locus determined using GENALEX 6.0.
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Fig2: Frequency distribution of the allele lengths (bp) at 10 microsatellite loci in the threeP. falciparumpopulations. Allele sizes determined by capillary electrophoresis are shown on the x-axis and their frequencies on the y-axis. Vertical bars for each population represent allele frequencies of major alleles for each microsatellite locus determined using GENALEX 6.0.

Mentions: A total of 196 isolates of P. falciparum infections only were reported. Of the 12 microsatellite loci genotyped, 2 (TA87 and TA1) gave less efficient PCR amplification and were therefore excluded from subsequent analyses. The allelic frequencies at each of the ten loci in each of the three parasite populations are presented in Figure 2. The overall number of alleles per locus observed in the study areas ranged from 8 (for locus 2490) to 27 (for locus TA81). Highest and lowest mean MOIs were recorded in BDG and AMK respectively (Table 1) although the difference across the populations was not significant (P = 0.637). Allelic diversity values were similar across all populations, with mean HE values across all loci between 0.65 (for LEK) and 0.79 (for AMK) (Table 2). Mann–Whitney U-test result showed no significant difference in the mean HE values between LEK and BDG as well as BDG and AMK at P < 0.01. However, the difference in the HE values between LEK and AMK was significant (P = 0.01). Although the mean number of genotypes detected per isolate was highest in AMK (Table 3), Kruskal-Wallis test (P = 0.368) showed no substantial difference in the mean number of genotypes in the three parasite populations.Figure 2


Microsatellite markers reveal low levels of population sub-structuring of Plasmodium falciparum in southwestern Nigeria.

Oyebola MK, Idowu ET, Nyang H, Olukosi YA, Otubanjo OA, Nwakanma DC, Awolola ST, Amambua-Ngwa A - Malar. J. (2014)

Frequency distribution of the allele lengths (bp) at 10 microsatellite loci in the threeP. falciparumpopulations. Allele sizes determined by capillary electrophoresis are shown on the x-axis and their frequencies on the y-axis. Vertical bars for each population represent allele frequencies of major alleles for each microsatellite locus determined using GENALEX 6.0.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4300683&req=5

Fig2: Frequency distribution of the allele lengths (bp) at 10 microsatellite loci in the threeP. falciparumpopulations. Allele sizes determined by capillary electrophoresis are shown on the x-axis and their frequencies on the y-axis. Vertical bars for each population represent allele frequencies of major alleles for each microsatellite locus determined using GENALEX 6.0.
Mentions: A total of 196 isolates of P. falciparum infections only were reported. Of the 12 microsatellite loci genotyped, 2 (TA87 and TA1) gave less efficient PCR amplification and were therefore excluded from subsequent analyses. The allelic frequencies at each of the ten loci in each of the three parasite populations are presented in Figure 2. The overall number of alleles per locus observed in the study areas ranged from 8 (for locus 2490) to 27 (for locus TA81). Highest and lowest mean MOIs were recorded in BDG and AMK respectively (Table 1) although the difference across the populations was not significant (P = 0.637). Allelic diversity values were similar across all populations, with mean HE values across all loci between 0.65 (for LEK) and 0.79 (for AMK) (Table 2). Mann–Whitney U-test result showed no significant difference in the mean HE values between LEK and BDG as well as BDG and AMK at P < 0.01. However, the difference in the HE values between LEK and AMK was significant (P = 0.01). Although the mean number of genotypes detected per isolate was highest in AMK (Table 3), Kruskal-Wallis test (P = 0.368) showed no substantial difference in the mean number of genotypes in the three parasite populations.Figure 2

Bottom Line: No matching multilocus haplotypes were found and analysis of multilocus LD showed no significant index of association.Genetic differentiation between populations was low (ΦPT = 0.017).The absence of detectable population structure of P. falciparum in southwestern Nigeria is evident in the lack of significant differentiation between populations separated by about 200 km.

View Article: PubMed Central - PubMed

Affiliation: Medical Research Council, Gambia Unit, Fajara, The Gambia. angwa@mrc.gm.

ABSTRACT

Background: Genetic diversity studies provide evidence of Plasmodium falciparum differentiation that could affect fitness and adaptation to drugs and target antigens for vaccine development. This study describes the genetic structure of P. falciparum populations in urban and rural sites from southwestern Nigeria.

Methodology: Ten neutral microsatellite loci were genotyped in 196 P. falciparum infections from three localities: Aramoko-Ekiti, a rural community; Lekki, an urban location and Badagry, a peri-urban border settlement. Analysis was performed on the genetic diversity, linkage disequilibrium, population structure and inter-population differentiation.

Results: Allelic diversity values were similar across all populations, with mean expected heterozygosity (HE) values between 0.65 and 0.79. No matching multilocus haplotypes were found and analysis of multilocus LD showed no significant index of association. Genetic differentiation between populations was low (ΦPT = 0.017).

Conclusion: The absence of detectable population structure of P. falciparum in southwestern Nigeria is evident in the lack of significant differentiation between populations separated by about 200 km. This implies that a fairly uniform malaria control strategy may be effective over a wide geographic range in this highly endemic region. However, more wide-scale survey across the country will be required to inform malaria control in this large and densely populated endemic region.

Show MeSH
Related in: MedlinePlus