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Aims to develop microsatellite markers for studies of genetic population structure in Anopheles dirus mosquitoes. Isolation of 11 microsatellite loci from A. dirus A and their utility in other members of Leucosphyrus group; Primer and core sequences; Variability of each locus; Number of alleles.

The population genetic structure of the Anopheles gambiae in westernKenya was studied using length variation at five microsatellite lociand sequence variation in a 648-nt mtDNA fragment. Mosquitoes were collected from houses in villages spanning up to 50 km distance. The following questions were answered. (i) Are mosquitoes in a house more related genetically to each other than mosquitoes between houses? (ii) What degree of genetic differentiation occurs on these geographicalscales? (iii) How consistent are the results obtained with both types of genetic markers? At the house level, no differentiation was detected by F{sub}ST{end} and R{sub}ST{end}, and the band sharing index test revealed no significant associations of alleles across loci. Likewise, indices of kinship based on mtDNA haplotypes in houses were even lower than in the pooled sample. Therefore, the hypothesis that mosquitoes in a house are more related genetically was rejected. At increasing geographical scales, microsatellite allele distributions were similar among all population samples and no subdivision of the gene pool was detected by F{sub}ST{end} or R{sub}ST{end}. Likewise, estimates of haplotype divergence of mtDNA between populations were not higher than the within population estimates, and mtDNA-based F{sub}ST{end} values were not significantly different from zero. That sequence variation in mtDNA provided matching results with microsatellite loci (while high genetic variation was observed in all loci), suggested that this pattern represents the whole genome. The minimum area associated with a deme of A.gambiae in western Kenya is therefore larger than50 km in diameter. [ABSTRACT FROM AUTHOR]

Genetic structure and species relationships were studied in three closely related mosquito species, Anopheles dirus A, C and D in Thailand using 11 microsatellite loci and compared with previous mitochondrial DNA (mtDNA) data on the same populations. All three species were well differentiated from each other at the microsatellite loci. Given the almost complete absence of mtDNA differentiation between An. dirus A and D, this endorses the previous suggestion of mtDNA introgression between these species. The high degree of differentiation between the northern and southern population of An. dirus C (RST = 0.401), in agreement with mtDNA data, is suggestive of incipient species. The lack of genetic structure indicated by microsatellites in four populations of An. dirus A across northern Thailand also concurs with mtDNA data. However, in An. dirus D a limited but significant level of structure was detected by microsatellites over ~400 km in northern Thailand, whereas the mtDNA detected no population differentiation over a much larger area (>1200 km). There is prior evidence for population expansion in the mtDNA. If this is due to a selective sweep originating in An. dirus D, the microsatellite data may indicate greater barriers to gene flow within An. dirus D than in species A. Alternatively, there may have been historical introgression of mtDNA and subsequent demographic expansion which occurred first in An. dirus D so enabling it to accumulate some population differentiation. In the latter case the lack of migration-drift equilibrium precludes the inference of absolute or relative values of gene flow in An. dirus A and D.