Decoding genetic power of adult female mosquitoes: Simplicity or complexity?
Rajnikant Dixit
Scientist D, National Institute of Malaria Research, Delhi, India
* Corresponding Author Email: dixit2k@yahoo.com | Tel: +919540509397
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Introduction
Mosquitoes that
belongs to order Diptera and Culicidae family, accounts a large group of
insects inhabiting throughout the temperate and tropical regions. Currently, a
total of 3,540 mosquito species have been recognized in the world, divided into
two subfamilies and 112 genera (Harbach 2007; 2014). Increased numbers of the
new mosquito species could be expected, with more discoveries and naming of
sibling species mainly in Anopheles. After Brazil, Indonesia, Malaysia and
Thailand, India is ranked fifth with high mosquito biodiversity, harboring more
than 393 mosquito species (Bhattacharyya et al. 2014).
A high richness of Anopheles mosquito
biodiversity seems to be an important contributory factor affecting millions of
lives through transmission of deadliest vector-borne disease malaria around the
globe. To save human life from the mosquito bites, chemical insecticides still
play a central role, however, the rapid rate of the development of insecticide
resistance demands the development of new molecular tools. The complex diverse
nature of mosquitoes poses various challenges to the vector biologists to such
as understanding the mechanism by which mosquitoes successfully feed, adapt and
survive in diverse ecologies; manage seasonal dependent massive breeding; fight
and manage pathogenic infections; which popularize them as a most dangerous
animal on the earth (https://www.statista.com/chart/ 2203/ the-worlds-deadliest-animals/).
One way we can
understand the mosquito’s abilities by considering their simplicity to adapt
and adjust their lifestyle wherever they may get favorable mosquitogenic
conducive environment, especially the availability of animal blood meal source
and non-toxic larval habitat. Due to this ability, a great shift could be seen
in response to fast urbanization supporting their growth.Cross border barriers
infiltration through increased air-traffic, seaways shipment carrying
mosquitogenic cargo, goods also induces the viable strains inoculums of new
mosquito species. To check the risk of induction of new mosquito fauna through
the air or water traffic WHO has issued guidelines (WHO 2016). Thus decoding a
functional correlation that's how non-genetic factors influence the mosquito
genetic factors, a power that drives and enables
mosquitoes to survive
in diverse ecologies, is expected to lead new tool development.
However, the
cracking and decoding the secrets of the mosquito success is not a simple job,
as proposed above. A recent whole genome sequencing and comparison of more than
16 malarial vector species showed a significant variation in the genome size,
encoded transcripts and their protein numbers etc. (Neafsey et al. 2015;
www.vectorbase.org). A comprehensive literature survey suggests that the
evolution and adaptation to blood feeding behavior in the adult female mosquito
is one of the key events which not only have favored mosquito’s reproductive
success but also supported successful development and transmission of many
pathogens. Hardwired genetic makeup poses a challenge to understand how complex
events e.g. feeding, mating, breeding, infection susceptibility, immunity etc.
are managed by mosquitoes.
Thus, using
functional genomics approaches, it could be clarified that how species-specific
genetic variation influences the distinct biology of a local mosquito vector
species/strain. For example, our recent findings of salivary gene expression
switching and pilot discovery of plant-like transcripts (Sharma et al. 2015a;
Sharma et al. 2015b), for the first time decoded the dual feeding associated
molecular complexity in the mosquito, A.
culicifacies. Thus, to fully
unlock the secrets of mosquito’s genetic
power we suggest an integrated research program focused to crack and identify
key genetic factors, regulating complex biology of (i) host-seeking and blood
feeding behavior; (ii) immunity and resistance to pathogen; and (iii)
reproductive success of mosquitoes is
needed (Figure 1).
References
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