In recent years a surprising finding has been the indication that Anopheles gambiae s.s. includes distinct “chromosomal forms” identified with non- Linnean names describing their locality or habitat, Mopti, Bamako, Forest, Savanna, and Bissau. Molecular studies of these “forms” have confirmed the existence of genetic discontinuity in An. gambiae s.s. The M and S molecular forms are differentiated at the rDNA (X chromosome) by diagnostic sites in the intergenic (IGS) region. These forms generally correspond to the Mopti and Savanna chromosomal forms, respectively. A parallel screen of variants in the internal transcribed spacer region (ITS) found three distinct ITS variants (Type I, II, and III). The first two are in complete linkage with the S and M molecular forms, respectively. Type III was only found in a small sample from the population of Sao Tome’, belonging to the M form. More recently variation in the intron I of the voltage-gated sodium gene has been found to co-segregate with the ITS and IGS site that define the M and S molecular forms. The finding of an unique ITS variant (Type III) on Sao Tome’, an island 300 km off the coast of West Africa, stimulated us to take a deeper look at the pattern of genetic differentiation between and within 3 populations on this island and the neighbouring island of Principe. The aims were to verify the existence of the ITS-TypeIII haplotype, previously described only on a few individuals from a population, and to attempt to understand its evolutionary origin. The same set of individuals was also screened for variation at the Intron I region of the voltage-gated channel gene and for variation at the mtDNA ND5 gene. We interpret these data in an expanded phylogeographic context, which include populations from continental Africa for both DNA regions. We also compare our results with the ones from a previous microsatellite survey. The results are of relevance in understanding levels of genetic differentiation and genetic isolation of these populations and in providing baseline data on multiple loci for future control interventions.

Garren, M., Santolamazza, F., Pinto, J., Gentile, G., Powell, J., Della Torre, A., et al. (2004). Geographic differentiation at multiple loci in Anopheles gambiae populations from São Tomé and Príncipe (West Africa).. In Abstracts (pp.301-302).

Geographic differentiation at multiple loci in Anopheles gambiae populations from São Tomé and Príncipe (West Africa).

GENTILE, GABRIELE;CACCONE, ADALGISA
2004-01-01

Abstract

In recent years a surprising finding has been the indication that Anopheles gambiae s.s. includes distinct “chromosomal forms” identified with non- Linnean names describing their locality or habitat, Mopti, Bamako, Forest, Savanna, and Bissau. Molecular studies of these “forms” have confirmed the existence of genetic discontinuity in An. gambiae s.s. The M and S molecular forms are differentiated at the rDNA (X chromosome) by diagnostic sites in the intergenic (IGS) region. These forms generally correspond to the Mopti and Savanna chromosomal forms, respectively. A parallel screen of variants in the internal transcribed spacer region (ITS) found three distinct ITS variants (Type I, II, and III). The first two are in complete linkage with the S and M molecular forms, respectively. Type III was only found in a small sample from the population of Sao Tome’, belonging to the M form. More recently variation in the intron I of the voltage-gated sodium gene has been found to co-segregate with the ITS and IGS site that define the M and S molecular forms. The finding of an unique ITS variant (Type III) on Sao Tome’, an island 300 km off the coast of West Africa, stimulated us to take a deeper look at the pattern of genetic differentiation between and within 3 populations on this island and the neighbouring island of Principe. The aims were to verify the existence of the ITS-TypeIII haplotype, previously described only on a few individuals from a population, and to attempt to understand its evolutionary origin. The same set of individuals was also screened for variation at the Intron I region of the voltage-gated channel gene and for variation at the mtDNA ND5 gene. We interpret these data in an expanded phylogeographic context, which include populations from continental Africa for both DNA regions. We also compare our results with the ones from a previous microsatellite survey. The results are of relevance in understanding levels of genetic differentiation and genetic isolation of these populations and in providing baseline data on multiple loci for future control interventions.
Annual Meeting of the American Society of Tropical Medicine and Hygiene
Miami (USA)
2004
53
American Society of Tropical Medicine and Hygiene
Rilevanza internazionale
contributo
2004
Settore BIO/05 - ZOOLOGIA
English
http://www.ajtmh.org/content/71/4_suppl/225.full.pdf+html
Intervento a convegno
Garren, M., Santolamazza, F., Pinto, J., Gentile, G., Powell, J., Della Torre, A., et al. (2004). Geographic differentiation at multiple loci in Anopheles gambiae populations from São Tomé and Príncipe (West Africa).. In Abstracts (pp.301-302).
Garren, M; Santolamazza, F; Pinto, J; Gentile, G; Powell, J; Della Torre, A; Caccone, A
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2108/40198
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