Navigation Links
Worm genome offers clues to evolution of parasitism
Date:9/24/2008

The genome of a humble worm that dines on the microbial organisms covering the carcasses of dead beetles may provide clues to the evolution of parasitic worms, including those that infect humans, say scientists at Washington University School of Medicine in St. Louis and the Max-Planck Institute for Developmental Biology in Germany.

In a paper published in the current issue of Nature Genetics, the researchers reported finding some surprises as they have decoded the genome of the worm, a tiny nematode called Pristionchus pacificus.

"We found a larger number of genes than we expected," says Sandra Clifton, Ph.D., research assistant professor of genetics and a co-author of the paper. "These include genes that help the worms live in a hostile environment, the result of living in and being exposed to the byproducts of decaying beetle carcasses, and others that also have been found in plant parasitic nematodes. The genome supports the theory that P. pacificus might be a precursor to parasitic worms."

Scientists estimate there are tens of thousands of nematode species. The worms are typically just one millimeter long and can be found in every ecosystem on Earth. Parasitic nematodes can infect humans as well as animals and plants.

One nematode in particular is well known in scientific circles: Caenorhabditis elegans has long been used as a model organism in research laboratories. Its genome sequence was completed in 1998 by Washington University genome scientists working as part of an international research collaboration.

Unlike C. elegans, which lives in the dirt, P. pacificus makes its home in an unusual ecological niche: it lives together with oriental beetles in the United States and Japan in order to devour the bacteria, fungi and other small roundworms that grow on beetle carcasses after they have died. While the beetles are alive and the nematodes' food source is scarce, the worms live in a "resting" stage in which they don't eat or reproduce.

This suspended state, called dauer diapause, is thought to be the infective state of parasitic nematodes. According to the World Health Organization, parasitic nematodes infect about 2 billion people worldwide and severely sicken some 300 million.

The genome of P. pacificus is substantially larger and more complex than C. elegans. It has nearly 170,000 chemical bases and contains 23,500 protein-coding genes. By comparison, C. elegans and the human parasitic nematode Brugia malayi, whose genome was sequenced in 2007, only have about 20,000 and 12,000 protein-coding genes, respectively. Infection with B. malayi causes lymphatic filariasis, which can lead to elephantiasis, a grotesque enlargement of the arms, legs and genitals.

Interestingly, the P. pacificus genome contains a number of genes for cellulases - enzymes that are required to break down cell walls of plants and microorganisms. These genes are nonexistent in C. elegans, although they have been found in plant parasitic nematodes.

"Using genetic tools, we can analyze the development, behavior and ecology of this highly unusual worm to aid in understanding the evolutionary changes that allowed parasitism to occur," says co-author Richard K. Wilson, Ph.D., director of Washington University's Genome Sequencing Center.


'/>"/>

Contact: Caroline Arbanas
arbanasc@wustl.edu
314-286-0109
Washington University School of Medicine
Source:Eurekalert

Related biology news :

1. NC State researchers get to root of parasite genome
2. TGen investigators devise faster, cheaper way of analyzing the human genome
3. DOE JGI extends the capabilities of the Integrated Microbial Genome System
4. Leader of Human Genome Project honored with the Inamori Ethics Prize
5. ISU researchers help map first plant-parasitic nematode genome sequence
6. Trichoplax genome sequenced -- rosetta stone for understanding evolution
7. Genome of simplest animal reveals ancient lineage, confounding array of complex capabilities
8. Genome of saltwater creature could aid understanding of gene grouping
9. Cataloguing invisible life: Microbe genome emerges from lake sediment
10. Duke-NIEHS team shows how DNA repairs may reshape the genome
11. Significant impact factor boost for scientific journal Genome Research
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/17/2017)... , April 17, 2017 NXT-ID, Inc. (NASDAQ: ... announces the filing of its 2016 Annual Report on Form 10-K ... Commission. ... 10-K is available in the Investor Relations section of the Company,s ... the SEC,s website at http://www.sec.gov . 2016 Year ...
(Date:4/11/2017)... Apr. 11, 2017 Research and Markets has ... report to their offering. ... The global eye tracking market to grow at a CAGR of ... Eye Tracking Market 2017-2021, has been prepared based on an in-depth ... market landscape and its growth prospects over the coming years. The ...
(Date:4/5/2017)... , April 5, 2017  The Allen Institute ... Allen Cell Explorer: a one-of-a-kind portal and dynamic digital ... 3D imaging data, the first application of deep learning ... human stem cell lines and a growing suite of ... platform for these and future publicly available resources created ...
Breaking Biology News(10 mins):
(Date:10/11/2017)... the Netherlands and LAGUNA HILLS, Calif. ... The Institute of Cancer Research, London ... use MMprofiler™ with SKY92, SkylineDx,s prognostic tool to risk-stratify patients ... trial known as MUK nine . The University of ... trial, which is partly funded by Myeloma UK, and ICR ...
(Date:10/11/2017)... , ... October 11, 2017 , ... ... the implantation and pregnancy rates in frozen and fresh in vitro fertilization ... progesterone and maternal age to IVF success. , After comparing the results from ...
(Date:10/10/2017)... ... October 10, 2017 , ... San Diego-based team building ... corporate rebranding initiative announced today. The bold new look is part of a ... company moves into a significant growth period. , It will also expand its service ...
(Date:10/10/2017)... ... October 10, 2017 , ... For the second time in ... STEM Mentoring Award. Representatives of the FirstHand program travelled to Washington, D.C. Tuesday, ... , US2020’s mission is to change the trajectory of STEM education in America ...
Breaking Biology Technology: