Scientists At J. Craig Venter Institute Publish Draft Genome Sequence From Aedes Aegypti, Mosquito Responsible For Yellow Fever, Dengue Fever

The fight against
yellow fever and dengue fever was advanced today by an international team
of researchers led by Vishvanath Nene, Ph.D. of the J. Craig Venter
Institute who sequenced the Aedes aegypti genome, the mosquito that carries
these deadly diseases. The research was published in the journal "Science."



This research is the first characterization of the approximately 1.38
billion base pairs of DNA of the Ae. aegypti genome. From this sequence,
the team showed that this mosquito species has an estimated 15, 419 protein
encoding genes.



Since both the sequence of the fruit fly, Drosophila melanogaster
(sequenced in 1999 and published in 2000) and another mosquito species,
Anopheles gambiae, (sequenced and published in 2002) were available,
researchers were able to compare these insects to Ae. aegypti to ascertain
biological differences between the species.



An. gambiae diverged on the evolutionary tree from the fruit fly about
250 million years ago, and the two mosquito species diverged from one
another approximately 150 million years ago. Genomic comparisons revealed
greater differences between the fruit fly and the mosquito species, than
between the two mosquito species.



An important finding from this analysis is the discovery of certain
proteins and genes unique to the Ae. aegypti. These proteins and genes,
among many things, infer robustness to the insect. A more thorough analysis
of these genes and proteins may lead to improved means to eradicate the
mosquito and thereby stop the spread of yellow and dengue fevers.



Another key discovery was that almost 50 percent of the genome
consisted of transposable elements. These are movable pieces of DNA that
cause mutations and can affect genome size. The researchers showed that
likely due to these elements the gene length and the intergenic regions of
Ae. aegypti are 4-6 times larger than those of An. gambiae and the fruit
fly.



"With more than half a million cases of dengue fever which is endemic
in at least 100 countries and more than 30,000 deaths from yellow fever
each year, clearly understanding the biology of the vector for these two
worldwide killers is essential to eradicating these diseases," said Dr.
Nene, principal investigator. "By having the genomic code of this species
of mosquito we now have a key tool that will aid in the study of aspects of
biology specific to Aedes aegypti. This will to help identify pathways
which permit these mosquitoes to transmit viruses. Interfering with the
function of critical mosquito molecules could lead to effective control of
this prolific pest and the devastating diseases associated with it."




The scientists concluded that this draft genome will enable continued
and more refined genomic maps of this disease vector. And, with other
ongoing genome sequencing and analysis projects of related mosquito
species, the spectrum of knowledge about these disease carriers grows, as
does the potential to eliminate the associated diseases that kill millions
each year.



This work was mainly funded by contracts from the United States
National Institutes of Health's National Institute of Allergy and
Infectious Diseases (NIAID). This research was first undertaken at The
Institute for Genomic Research (TIGR), a legacy organization of the J.
Craig Venter Institute, and in collaboration with The Broad Institute and
VectorBase, a NIAID bioinformatics resource center. TIGR became part of the
JCVI in October 2006.



About the J. Craig Venter Institute



The J. Craig Venter Institute is a not-for-profit research institute
dedicated to the advancement of the science of genomics; the understanding
of its implications for society; and communication of those results to the
scientific community, the public, and policymakers. Founded by J. Craig
Venter, Ph.D., the JCVI is home to approximately 500 scientists and staff
with expertise in human and evolutionary biology, genetics,
bioinformatics/informatics, information technology, high-throughput DNA
sequencing, genomic and environmental policy research, and public education
in science and science policy. The legacy organizations of the JCVI are:
The Institute for Genomic Research (TIGR), The Center for the Advancement
of Genomics (TCAG), the Institute for Biological Energy Alternatives
(IBEA), the Joint Technology Center (JTC), and the J. Craig Venter Science
Foundation. The JCVI is a 501 (c)(3) organization. For additional
information, please visit JCVI.


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