Evidence of multiple chromosomal inversions in Aedes aegypti formosus from Senegal

Chromosomal inversions are prevalent in mosquito species but polytene chromosomes are difficult to prepare and visualize in members of the tribe Aedinii and thus there exists only indirect evidence of inversions. We constructed an F₁ intercross family using a P₁ female from a laboratory strain of Aedes aegypti aegypti (Aaa) and a P₁ male Aedes aegypti formosus (Aaf) from a strain collected from south-eastern Senegal. Recombination rates in the F₂ offspring were severely reduced and genotype ratios suggested a deleterious recessive allele on chromosome 3. The F₂ linkage map was incongruent in most respects with the established map for Aaa. Furthermore, no increased recombination was detected in F₅ offspring. Recombination rates and gene order were consistent with the presence in Aaf of at least four large inversions on chromosome 1, a single small inversion on chromosome 2 and three inversions on chromosome 3.