Identification of a polymorphic mucin-like gene expressed in the midgut ofthe mosquito, Aedes aegypti, using an integrated bulked segregant and differential display analysis

The identification of putative differentially expressed genes within genome regions containing QTL determining susceptibility of the mosquito, Aedes a egypti, to the malarial parasite, Plasmodium gallinaceum, was investigated using an integrated, targeted approach based on bulked segregant and differ ential display analysis. A mosquito F-2 population was obtained from pairwi se matings between the parasite-susceptible RED strain and the resistant MO YO-R substrain. DNA from female carcasses was used to genotype individuals at RFLP markers of known chromosomal position around the major QTL (pgs 1). Midguts, dissected 48 hr after an infected blood meal, were used to prepar e two RNA bulks, each representing one of the parental genotypes at the QTL interval. The RNA bulks were compared by differential display PCR. A mucin -like protein gene (AeIMUC1) was isolated and characterized. The gene maps within the pgs 1 QTL interval and is expressed in the adult female midgut. AeIMUC1 RNA abundance decreased with time after blood meal ingestion. No di fferential expression was observed between the two mosquito strains but thr ee different alleles with inter- and intrastrain allelic polymorphisms incl uding indels and SNPs were characterized. The AelMUC1 gene chromosome locat ion and allelic polymorphisms raise the possibility that the protein might be involved in parasite-mosquito interactions.