Abstract:
Anopheles culicifacies, major vector of malaria in Sri Lanka is a five member species
complex. Differences of the vector competence of siblings, is still poorly delineated.
Therefore, the current study was carried out to observe any relationship of the variations
in vector competence to ITS2 nucleotide sequences and secondary structure
characteristics of the species complex. DNA was extracted from sibling species B and E,
the ITS2 region was amplified and sequenced. Sequences for A, C and D siblings were
retrieved from NCBI GenBank. The complex divided into two groups, AD and BCE
based on primary and secondary structure of the ITS2 sequences. Secondary structures of
all species had three helices where pyrimidine-pyrimidine mismatch in Helix II and a
UUUGG motif at 5‘ of Helix III were displayed only for B, C and E. Among five types of
loops, interior and exterior loops were more conserved than other loop types. Results
showed the major vector sibling E and poor or non vector sibling B shares identical
nucleotide sequence and secondary structure. Therefore, ITS2 secondary structure is
independent of the vector competence of the sibling species.
