GULF OF GUINEA ISLANDS' BIODIVERSITY
NETWORK
AN ISLAND WITHIN AN ISLAND: GENETIC DIFFERENTIATION OF Anopheles gambiae IN São Tomé, WEST AFRICA, AND ITS RELEVANCE TO MALARIA VECTOR CONTROL. Heredity 91: 407-414.
Pinto, J.1, Donnelly, M. J.2, Sousa, C. A.3, Maltas-Vacas, J.1, Gil, V.4, Ferreira, C.4, Petrarca, V.5, Rosário, V. E. do1* and Charlwood, J. D. 1 ,6.
Address: 1 Centro de Málaria e
outras Doenças Tropicais, Instituto de Higiene e Medicina Tropical,
Universidade Nova de Lisboa, Rua da
Junqueira 96, 1349-008 Lisbon, Portugal
2 Vector Research Group, Liverpool School of Tropical Medicine, Pembroke Place,
Liverpool L3 5QA, UK.
3 Unidade de Entomologia Médica, Instituto de Higiene e
Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira 96, 1349-008 Lisbon, Portugal
4 Centro Nacional de Endemias, Ministério de Saúde, C.P. 218, São Tomé, Democratic
Republic
of São Tomé and Príncipe
5 Dipartimento di Genetica e Biologia Molecolare, Universitá di Roma 'La Sapienza', P.le Aldo Moro 5,
Rome 00815, Italy
6. Danish Bilharziasis Laboratories, 1-D Jaergersborg Allé, Charlottenlund, DK
2920, Denmark
* Corresponding author
Abstract
Islands are choice settings for experimental studies of vector control strategies based on transgenic insects. Before considering this approach, knowledge of the population structure of the cevtor is essential. Genetic variation at 12 microsatellite loci was therefore studied in samples of the malaria vector Anopheles gambiae s.s., collected fromsix localities of São Tomé island (West Africa). The objectives were (i) to assess the demographic stability and effective population size of A. gambiae from these sites, (ii) to determine population differentiation and (iii) to relate the observed population patterns of population structure with geographic, ecological and historical aspects of the vector on the island. Significant population differentiation, revealed by FSTand RST statistics, was found between the southernmost site, Porto Alegre, and northern localities. The observed patterns of population substructure are probably a result of restrictions to gene flow in the less inhabited, more densely forested and mountainous south. In all localities surveyed, A. gambiae appeared to be experiencing a demographic expansion, consistent with a relatively recent (ca. 500 years) founder effect. The results are discussed with respect to current and future prospects of malaria vector control.
Heredity 2003 91: 407-414