Using 454 technology for long-PCR based sequencing of the complete mitochondrial genome from single Haemonchus...

Mitochondrial (mt) genomes represent a rich source of molecular markers for a range of applications, including population genetics, systematics, epidemiology and ecology. In the present study, we used 454 technology (or the GS20, massively parallel picolitre reactor platform) to determine the complete mt genome of Haemonchus contortus (Nematoda: Trichostrongylidae), a parasite of substantial agricultural, veterinary and economic significance. We validate this approach by comparison with mt sequences from publicly available expressed sequence tag (EST) and genomic survey sequence (GSS) data sets.

The complete mt genome of Haemonchus contortus was sequenced directly from long-PCR amplified template utilizing genomic DNA (~20-40 ng) from a single adult male using 454 technology. A single contig was assembled and compared against mt sequences mined from publicly available EST (NemBLAST) and GSS datasets. The comparison demonstrated that the 454 technology platform is reliable for the sequencing of AT-rich mt genomes from nematodes. The mt genome sequenced for Haemonchus contortus was 14,055 bp in length and was highly AT-rich (78.1%). In accordance with other chromadorean nematodes studied to date, the mt genome of H. contortus contained 36 genes (12 protein coding, 22 tRNAs, rrnL and rrnS) and was similar in structure, size and gene arrangement to those characterized previously for members of the Strongylida.

The present study demonstrates the utility of 454 technology for the rapid determination of mt genome sequences from tiny amounts of DNA and reveals a wealth of mt genomic data in current databases available for mining. This approach provides a novel platform for high-throughput sequencing of mt genomes from nematodes and other organisms.