DEVELOPMENT OF A COMPARATIVE GENETIC-LINKAGE MAP FOR ARMIGERES SUBALBATUS USING AEDES-AEGYPTI RFLP MARKERS

One of the causative agents of lympahtic filariasis is the nematode pa rasite Brugia malayi that requires a competent mosquito vector for its development and transmission. Armigeres subalbatus mosquitoes rapidly destroy invading B. malayi microfilariae via a defense response known as melanotic encapsulation. We have constructed a genetic linkage map for this mosquito species using RFLP markers from Aedes aegypti. This heterologous approach was possible because of the conserved nature of the coding sequences used as markers and provided an experimental fra mework to evaluate the hypothesis that linkage and gene order are cons erved between these mosquito species. Of the 56 Ae, aegypti markers te sted, 77% hybridize to genomic DNA digests of Ar. subalbatus under str ingent conditions, with 53% of these demonstrating strain-specific pol ymorphisms. Twenty-six Ae, aegypti markers have been mapped using an F -2-segregating Ar. subalbatus population derived from a cross of strai ns originating in Japan and Malaysia. Linear order of these marker loc i is highly conserved between the two species. Only 1 of these markers , LF92, was not linked in the manner predicted by the Ae. aegypti map. In addition, the autosomal sex-determination locus that occurs in lin kage group 1 in Ae. aegypti resides in group 3 in Ar, subalbatus. The Ar. subalbatus map provides a basic genetic context that can be utiliz ed in further genetic studies to clarify the genetic basis of parasite resistance in this mosquito and is a necessary precursor to the ident ification of genome regions that carry genes that determine the encaps ulation phenotype.