a1 Institute of Cell, Animal and Population Biology, University of Edinburgh, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, Scotland, U.K.
Serotyping with monoclonal antibodies was used to estimate the number and frequencies of allelic variants of two merozoite surface proteins, MSP1 and MSP2, and an exported protein Exp-1, in a sample of 344 clinical isolates of Plasmodium falciparum from an urban region of The Gambia. Represented among the isolates were 36, 8 and 2 alleles of the MSP1, MSP2 and Exp-1 loci respectively. Relative frequencies of these alleles remained stable in the parasite population over the 2 years of the study. A computer program was used to calculate from the frequencies of individual alleles at the three loci, the probable number of different genotypes in samples from the population, assuming random assortment among the loci. No significant difference was found between the expected and the observed genotype diversity. It is concluded that recombination among unlinked loci is a common consequence of sexual reproduction of P. falciparum in The Gambia. Slightly lower genotype diversity was observed in each of two villages, which may be a consequence of smaller population size compared with the urban region.
(Received September 27 1990)
(Revised February 14 1991)
(Accepted February 14 1991)
p1 Present address: Department of Pure and Applied Biology, Imperial College, London SW7 2BB.
† Reprint requests to J. S. McBride.