Plant & Animal Genomes XIV Conference

January 14-18, 2006
Town & Country Convention Center
San Diego, CA

Identification And Analysis Of Genes Expressed In The Adult Filarial Parasitic Nematode Dirofilaria immitis

YONG YIN¹ , John Martin¹ , James P. McCarter^{1, 2} , Sandra W. Clifton¹ , Richard K. Wilson¹ , Makedonka Mitreva¹

¹  Genome Sequencing Center, Washington University School of Medicine, St. Louis, MO 63108, USA

²  Divergence, Inc., St. Louis, MO 63141, USA

Projects are currently underway to characterize over 270,000 ESTs (Expressed Sequence Tags) that we have generated from ~30 parasitic nematode species during the past 5 years (www.nematode.net), including 4,000 ESTs from the adult dog heartworm Dirofilaria immitis. D. immitis has a worldwide distribution in temperate and tropical climates. In the United States, heartworm infection has been found in dogs native to all 50 states. Adult heartworms reside in the host pulmonary arteries and right ventricles for five to seven years, with the number of adults reaching up to 250 in a single dog, resulting in various fatal lung and heart diseases such as severe pulmonary arterial inflammation and congestive heart failure. Here we offer, for the first time, a detailed comparative genomics analysis of the adult D. immitis transcribed genome covering about 1,800 genes, using sequences generated from various genome sequencing projects, especially the on-going Brugia malayi project, which is being finished and is the only filarial nemotade genome currently available. We have revealed both the genes common to metazoans or nematodes, and the genes specific to filarial parasites or the heartworm. Putative functions of the heartworm genes have been classified by mapping to the Gene Ontology terms and the KEGG pathways. Crucial mechanisms of the adult heartworm, such as energy generation pathway and antioxidant defense system, have been discussed. Our analysis on D. immitis has thus generated insights that may relate to biology, parasitism, and evolution within the phylum Nematoda. The project is funded by grant NIH-NIAID-46593.