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Journal of Mosquito Research, 2013, Vol.3, No.9, 65
-
70
ISSN 1927-646X
http://jmr.sophiapublisher.com
65
Research Report
Open Access
Molecular Evolution and Phylogenomics of the
Anopheles gambiae
Complex
Benson Otarigho , Mofolusho O. Falade
Cellular Parasitology Programme, Cell Biology and Genetics Unit, Department of Zoology, University of Ibadan, Nigeria
Corresponding author email: folu7@yahoo.co.uk;
Authors
Journal of Mosquito Research, 2013, Vol.3, No.9 doi: 10.5376/jmr.2013.03.0009
Received: 26 Mar., 2013
Accepted: 03 Apr., 2013
Published: 26 Apr., 2013
Copyright
© 2013 Otarigho and Falade. This is an open access article published under the terms of the Creative Commons Attribution License, which permits
unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Otarigho and Falade, 2013, Molecular Evolution and Phylogenomics of the
Anopheles gambiae
Complex, Journal of Mosquito Research, Vol.3, No.9 65-70
(doi: 10.5376/jmr.2013.03.0009)
Abstract
Malaria vectors of the
Anopheles gambiae
complex are made up six species of mosquitoes that are stable and are highly
efficient vectors. This group comprises of major and minor vectors, some of which are responsible for transmission of the most
deadly strain of malaria parasite,
Plasmodium falciparum
. The evolutionary history of this species group was inferred using
publically available DNA sequence data. The retrieved sequences were aligned using CLUSTAL W; evolutionary history was
inferred using Maximum Likelihood, Neighbor-Joining, and Minimum Evolution methods. Ancestral sequences were also inferred
using the FASTML Server-based program for computing ancestral sequences. Based on morphology, ecology and behaviour,
Anopheles gambiae
and
Anopheles arabiensis
(major vectors) were found to evolve from a common ancestor. All the members of this
complex were all AT rich.
A. gambiae
and
A. arabiensis
had the highest AT composition, while
A. merus
was the least AT rich among
the complex. Evolutionary divergence estimates show that these two major vectors are genetically similar.
A. quadriannulatus
(non
vector) and
A. melas
(minor vector) were also found to evolve from the same ancestor. Overall, this study gives an understanding of
the ancestral lineage of the
A. gambiae
complex, which will be essential for understanding the origins, evolution, classification and
epidemiology of this important disease vector. This may have important implications for the control of malaria.
Keywords
Anopheles gambiae
complex; Vectorial capacity; Evolution; Phylogenetics; Cytochrome c oxidase (
COI
); Mitochoindria
DNA sequence; Evolutionary history; Evolutionary divergence
Introduction
Anopheles gambiae
is a complex of six
morphologically indistinguishable species of
mosquitoes in the genus
Anopheles
(Besansky et al.,
2003; Hunt et al., 1998). Major malaria vectors of the
A. gambiae
(Culicidae) complex includes (
A.
arabiensis
,
A. gambiae
), with minor vectors (
A.
bwambae
,
A. melas
,
A. merus
) and non-vectors (
A.
quadriannulatus
). There is an overlap in the presence
of
A. gambiae
and
A. arabiensis
in many regions
spread across many areas in sub-Saharan Africa
(Thelwell et al., 2000). In a small area around the
geothermal springs located in the Semuliki National
Park, Uganda there is a distinctive presence of
Anopheles bwambae
, where also
A. gambiae
and
A.
arabiensis
species of the genus may be found
(Harbach et al., 2007).
A. merus
and
A. melas
breed in
saltwater (Coluzzi et al., 1979).
A. quadriannulatus
is
a fresh water breeder, and although susceptible to
Plasmodium
infections, this species is not a natural
vector of human malaria mainly because of its zoophilic
behavior (Takken et al., 1999; Habtewold et al., 2008).
The ability to transmit Plasmodium efficiently makes
members of the
A. gambiae
complex highly important
vectors for public health and the scientific community.
Malaria is the most important disease transmitted by
the
A. gambiae
complex. This disease poses a great
threat to half of the world’s population, and there
are 300 million to 500 million clinical cases
annually, resulting in approximately 1.5 million to
2.7 million deaths (WHO, 2010; WHO, 2011).
Mosquitoes from the genus
Anopheles
are the only
genus that transmits Plasmodium, the malaria-causing
parasite. This genus is one of the most important of
the three genera in the Culicidae subfamily
Anophelinae. Of these families,
Anopheles
is the
largest, with 427 species making up the family
having an almost complete global presence