· We have sequenced 23,270 Taenia solium ESTs from two developmental states: 14,113 from the adult worm and 9,157 from the larvae (cysticercus). All these ESTs are available through NCBI-dbEST. Additionally, 25,700, 5' sequences obtained from full-length cDNA clones, and 12,000 3' sequences from the same library have been produced. Nearly 50% of T. solium coding sequences find a match in SwissProt. Automatic and manual annotation is under process.
· The information content of the Taenia solium genome is 130 Mb. However, assuming that Taenia is diploid, the DNA content in the cell nuclei, determined by fluorescence activated cell sorting (FACS) indicates that the haploid genome size is close to 260 Mb. Recently, a strategy for producing physical maps (Whole Genome Profiling) indicated a genome size near 260 Mb. Thus, our working hypothesis is that the Taenia genome resulted from a recent duplication of a 130 Mb genome.
· Genome sequencing has been carried out through a combined strategy using capillary and 454 sequencing. So far, we have processed about 725,000 sequences (as pair reads) by Sanger capillary sequencing, representing a coverage near 2X, and 56 runs of 454 pyrosequencing, equivalent to a coverage of about 5X (assuming a genome size of 260Mb). Hybrid assembly using both sequencing methods produces over 50,000 contigs with an N50 of 5000 nucs. At present, approximately 90% of Taenia ESTs sequences can be accounted by this assembly. We foresee that the final assembly will include 15 X coverage of 454 Titanium (400 nucs/read) and 30 X coverage of Solid (paired, 50 nucs/read).
· Results of this research have
been published in the 4 april 2013 issue of Nature as:
The genomes of four tapeworm species reveal adaptations to parasitism
Isheng J. Tsai, Magdalena Zarowiecki, Nancy Holroyd, Alejandro Garciarrubio, Alejandro Sanchez-Flores, Karen L. Brooks, Alan Tracey, Raúl J. Bobes, Gladis Fragoso, Edda Sciutto, Martin Aslett, Helen Beasley, Hayley M. Bennett, Jianping Cai, Federico Camicia, Richard Clark, Marcela Cucher, Nishadi De Silva, Tim A. Day, Peter Deplazes, Karel Estrada, Cecilia Fernández, Peter W. H. Holland, Junling Hou, Songnian Hu, Thomas uckvale, Stacy S. Hung, Laura Kamenetzky, Jacqueline A. Keane, Ferenc Kiss, Uriel Koziol, Olivia Lambert, Kan Liu,Xuenong Luo, Yingfeng Luo, Natalia Macchiaroli, Sarah Nichol, Jordi Paps, John Parkinson, Natasha Pouchkina-Stantcheva, Nick Riddiford, Mara Rosenzvit, Gustavo Salinas, James D. Wasmuth, Mostafa Zamanian, Yadong Zheng, The Taenia solium Genome Consortium, Xuepeng Cai, Xavier Soberón, Peter D. Olson, Juan P. Laclette, Klaus Brehm & Matthew Berriman
The Nature paper has been published digitally at: