Amplified Fragment Length Polymorphism Mapping of Quantitative Trait Loci for Malaria Parasite Susceptibility in the Yellow Fever Mosquito Aedes aegypti

Abstract

The yellow fever mosquito Aedes aegypti has been the subject of extensive genetic research due to its medical importance and the ease with which it can be manipulated in the laboratory. A molecular genetic linkage map was constructed using 148 amplified fragment length polymorphism (AFLP) and six singlestrand conformation polymorphism (SSCP) markers. Eighteen AFLP primer combinations were used to genotype two reciprocal F 2 segregating populations. Each primer combination generated an average of 8.2 AFLP markers eligible for linkage mapping. The length of the integrated map was 180.9 cM, giving an average marker resolution of 1.2 cM. Composite interval mapping revealed a total of six QTL significantly affecting Plasmodium susceptibility in the two reciprocal crosses of Ae. aegypti. Two common QTL on linkage group 2 were identified in both crosses that had similar effects on the phenotype, and four QTL were unique to each cross. In one cross, the four main QTL accounted for 64% of the total phenotypic variance, and digenic epistasis explained 11.8% of the variance. In the second cross, the four main QTL explained 66% of the variance, and digenic epistasis accounted for 16% of the variance. The actions of these QTL were either dominance or underdominance. Our results indicated that at least three new QTL were mapped on chromosomes 1 and 3. The polygenic nature of susceptibility to P. gallinaceum and epistasis are important factors for significant variation within or among mosquito strains. The new map provides additional information useful for further genetic investigation, such as identification of new genes and positional cloning.

An Integrated Linkage, Chromosome, and Genome Map for the Yellow Fever Mosquito Aedes aegypti

“…aegypti to transmit different pathogens. The QTLs associated with the transmission of dengue virus 2 (DEN2) [19], [20]; filarioid nematode Brugia malayi [17] and the avian malaria parasite Plasmodium gallinaceum [15], [18] are indicated by different colors on Figure 4. As a result of physical mapping, 12 QTLs on the linkage map “collapsed” into five clusters of QTLs on the chromosome map in regions: 1p31–34; 2p33–42; 2q31–32 and 3p31–32 (Figure 6).…”

“…A composite map for RFLP, SSCP, and SNP markers incorporated 146 loci and covered 205 cM [6]. Later, an additional map using amplified fragment-length polymorphism (AFLP) was also developed for 148 loci and covered about 180 cM of the genome [15]. Finally, the genetic map of Ae.…”

“…aegypti was extended by incorporating microsatellite loci [16]. The linkage map was used as a tool to localize several quantitative trait loci (QTLs) related to pathogen transmission: the filarioid nematode Brugia malayi [17], the avian malaria parasite Plasmodium gallinaceum [15], [18], and dengue virus [19], [20]. Among all mosquitoes, the map developed for Ae.…”

Genome Investigations of Vector Competence in Aedes aegypti to Inform Novel Arbovirus Disease Control Approaches

“…Subsequent QTL mapping studies in A. aegypti have confirmed a multigene mode of DENV vector competence and defined genome regions containing multiple independent QTL [70,71,72]. In addition, QTL studies on other pathogens, including the filarial worm parasite, Brugia malayi , and the malaria parasite, Plasmodium gallinaceum , identified multiple QTL [73,74,75,76]. Of note, these QTL tend to cluster in only five specific genome regions, irrespective of the pathogen or genetic background of the mosquito host [77], suggesting that these regions (Figure 1) may contain key mutations in loci that ultimately determine vector competence.…”

Amplified Fragment Length Polymorphism Mapping of Quantitative Trait Loci for Economically Important Traits in the Silkworm,Bombyx mori

“…Since high-resolution QTL mapping is critical for positional cloning and gene isolation (Zhong et al 2006), a high resolution AFLP-based genetic linkage map and the results of QTL mapping for economically important cocoon traits are reported.…”