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Volume 2, June 2017, pages 1-2

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

  1. Neafsey D, Waterhouse R, Abai M, Aganezov S, Alekseyev M, Allen J, Amon J, Arca B, Arensburger P, Artemov G et al. 2014.Highly evolvable malaria vectors: The genomes of 16 Anopheles mosquitoes.Science. 347:1258522-1258522.
  2. Bhattacharyya D, Rajavel A, Mohapatra P, Jambulingam P, Mahanta J, Prakash A. 2014. Faunal richness and the checklist of Indian mosquitoes (Diptera: Culicidae). Check List 10(6): 1342–1358
  3. Sharma P, Sharma S, Mishra A, Thomas T, Das De T, Rohilla S, Singh N, Pandey K, Valecha N, Dixit R. 2015a. Unraveling dual feeding associated molecular complexity of salivary glands in the mosquito Anopheles culicifacies. Biology Open. 4:1002-1015
  4. Sharma P, Das De T, Sharma S, Kumar Mishra A, Thomas T, Verma S, Kumari V, Lata S, Singh N, Valecha N et al. 2015b. Deep sequencing revealed molecular signature of horizontal gene transfer of plant like transcripts in the mosquito Anopheles culicifacies: an evolutionary puzzle. F1000Research.4:1523