Abstract:
Vector control is an essential component in elimination of malaria in Sri Lanka in which the
proper identification of vector mosquitoes from non-vector mosquitoes is insisted.
Anopheles subpictus, an important secondary vector of malaria in Sri Lanka, was recently
identified as a species complex of two sibling species, An. subpictus A and B. The objective
of this study was to further investigate and confirm the status of An. subpictus species
complex in Sri Lanka based on white gene sequences. This single copy nuclear gene white
is used in systematics studies in constructing phylogenetic relationships at species level.
This study reports sequence comparisons of the white gene in An. subpictus in Sri Lanka
for the first time. Adult F1 mosquitoes of An. subpictus from different isofemale progenies
belonging to five different localities in the island were used as specimens (n=30). A partial
region of white gene was PCR amplified and sequenced. There were fourteen haplotypes
of white gene which were submitted to GenBank under accession numbers, KP733780-
KP733793. Phylogenetic relationships among the mosquitoes were estimated using
PhyML v3.1 and MrBayes v3.2.2 software. The Maximum Likelihood and Bayesian
analyses revealed similar tree topologies with two distinct, strongly supported,
monophyletic clades which were consistent with previous studies, as Species A clade and
Species B clade. However, this putatively conserved single copy nuclear DNA marker
white, reliably indicated additional polymorphism in terms of further clustering of the two
main clades. In this context, bayesian inference gave more robust support on these sub
clades with all posterior probabilities exceeding 0.78. Present investigations on An.
subpictus species complex in Sri Lanka confirm the presence of two distinct sibling species
A and B based on white gene sequences. Furthermore, the white gene phylogeny together
with the fourteen white single copy nuclear gene haplotypes unravels clues of a hidden
diversity that may exist in the species complex. In conclusion, molecular evidence from this
study indicates the likelihood of the presence of a yet undiscovered sibling species for An.
subpictus s.l. in Sri Lanka.
