Inversions 2Rb, 2Rc, and 2Ru are shared between chromosomal forms, Bamako, Mopti, Savanna, Forest and Bissau of Anopheles gambiae s.s. a major malaria vector in Africa. Molecular analysis of these inversion breakpoints is essential for a better understanding of the chromosomal rearrangement mechanisms and knowledge of their structure and may lead to the development of PCR-based diagnostic assays that can be used to differentiate the chromosomal forms. We performed in situ hybridization and cloned DNA sequence analyses to identify and characterize these inversion breakpoints on chromosome 2Rbc/bc, in Mopti, on 2Rjcu/jcu in Bamako, and on 2Rb/b in Savanna. The 2Ru proximal breakpoint contained repetitive DNA and single copy gene sequences interrupted by the breakpoint. The 2Rb distal breakpoint contained an assembly of unique sequences and repetitive elements, including complete and degenerated transposable elements. The 2Ru proximal breakpoint features make it difficult to verify its genomic structure by PCR amplification. However, FISH and PCR analyses of this breakpoint provided a promising molecular assay to diagnose it in individual mosquitoes. PCR amplification of the 2Rb distal breakpoint confirmed the molecular structure (4085 bp of unique and repetitive sequences) described by sequence analyses and led to the first step in molecular karyotyping of the 2Rb inversion. The study described in this thesis provided groundwork for future molecular investigations (gene expression profile and sequence variation) of the 2Rb, 2Rc and 2Ru inversion breakpoints.