Sand Fly Genome Project
Photo copyright: Ray Wilson
About the Project
The BCM-HGSC is sequencing Lutzomyia longipalpis (Diptera: Psychodidae), a phlebotomine sand fly that transmits American visceral leishmaniasis caused by Leishmania infantum syn. chagasi one of the most important and dangerous of the parasites of the genus Leishmania.
The leishmaniasis group of diseases threatens around 350 million people in 88 countries around the globe. Many species of phlebotomine sand fly are inherently refractory to the full development of Leishmania. Thus of the 700 or so species described to date, only 10% have been incriminated as vectors.
Colonisation of urban areas by Lu. longipalpis is believed to be an important factor in the recent increase of visceral leishmaniasis in South America. Even in sub-tropical regions where these diseases have not traditionally been as important, their sub-clinical status has been elevated to clinical disease by association with HIV infection.
The Lu. longipalpis species is an excellent model for the study of these flies and their role in the spread of disease given its ability to allow the growth and transmission of a variety of Leishmania species such as L. mexicana and L. major, in addition to the only parasite that it transmits under natural conditions L. infantum syn. chagasi. The Leishmania are insect gut colonising parasites that are acquired during feeding on blood from an infected mammal.
Phlebotomine sand flies are small insects (adults 2-3mm), adults are light brown in colour, hairy with wings held in a distinctive v shape and the larvae are terrestrial, living in detritus.
The project is in collaboration with Rod Dillon’s lab at the Liverpool School of Tropical Medicine UK, who provided the biological material from a colony originally derived from flies obtained in Jacobina, Brazil more than 20 years ago.
Access to the Data
Genome assembly Llon 0.1 is now available for download here, and using the data link in the side bar. This is a very preliminary assembly that is being made available to the sand fly community to enable research. We believe the genome assembly is not as good as we would like, due to sequence polymorphism in the original sample, and the large number of individuals that were required to isolate sufficient DNA. As a result contig and scaffold sizes are small, and we have not performed any quality control measures as we are continuing to work on improving the assembly. Given the lack of genome data available to the community we have released this as a temporary assembly with a 0.1 designation, but please use at you own risk—caveat emptor! We have also made the contig and scaffold files blastable on our blast server to allow easy searching of the sequence.
We also sequenced 8 BACs, 5 of which were finished to phase 3 quality.
Updates about this genome are being posted to the sandfly genomics listserv. Please contact Stephen Richards with your email address to sign up.