Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Of Lice And Man: Researchers Sequence Human Body Louse Genome

22.06.2010
Like an unwelcome houseguest or itinerant squatter, the human body louse shows up when times are bad and always makes them worse. Now a multi-institutional team reports that it has sequenced the body louse genome, an achievement that will yield new insights into louse – and human – biology and evolution.

The study, which also sequenced the genome of a microbe that lives inside the body louse, appears in Proceedings of the National Academy of Sciences.

Thanks to its tenacity, the tiny, blood-sucking parasite Pediculus humanus humanus L. has witnessed, and played a role in, millions of years of human history. The body louse spread epidemic typhus and what is now termed trench fever to Napoleon’s retreating army in Russia in 1812, and body lice plagued Lewis and Clark on their adventures in the New World.

The human body louse seems to appear out of nowhere during economic downturns, wars and other crises that cause people to live in unsanitary conditions. It is closely related to the head louse, Pediculus humanus capitis, which also feeds on human blood. But the body louse lives in clothing and, unlike the head louse, can spread bacterial diseases.

The body louse genome is the smallest known genome of any insect, said University of Illinois entomology professor Barry Pittendrigh (pronounced PITT-in-dree), who led the drive to fund the project and coordinated the international team of scientists who analyzed the sequence. The size of the body louse genome probably reflects its rather protected habitat and predictable diet, he said.

“The ecology of lice is very, very simple. It either lives in your hair or on your clothing, and it has one type of meal, and that’s blood,” he said. “So most of the genes that are responsible for sensing or responding to the environment are very much reduced.”

The genome analysis found very few genes for light-sensing protein receptors, for example. University of Illinois entomology professor Hugh Robertson was responsible for sorting out the genes contributing to chemical sensing, and discovered that the louse has significantly fewer taste and odorant receptors than other insects.

The body louse also has “the smallest number of detoxification enzymes observed in any insect,” the researchers wrote. John Clark, of the University of Massachusetts at Amherst, and Si Hyeock Lee, of Seoul National University, led this part of the analysis. The body louse’s pared-down list of detoxifying enzymes makes it an attractive organism for the study of resistance to insecticides or other types of chemical defense, Pittendrigh said. University of Illinois entomology professor and department head May Berenbaum and former graduate student Reed Johnson contributed to this effort.

The body louse is completely dependent on humans for its survival; it will die if separated from its host for very long. It is just as reliant on a microbe that lives inside it: the bacterium Candidatus Riesia pediculicola.

In the Riesia genome, the team found genes for the production of an essential nutrient, pantothenate (Vitamin B5), which the louse requires and cannot make on its own.

The Riesia genome also is quite small in comparison to its closest “free-living” relatives. So too are the genomes of the bacterial pathogens that the body louse transmits to its human hosts: Rickettsia prowazekii (which causes epidemic typhus), Borrelia recurrentis (the agent of relapsing fever) and Bartonella quintana (which causes trench fever). This, the researchers report, will make the body louse a useful tool for understanding the co-evolution of disease-carrying parasites and their bacterial co-conspirators.

The body louse genome will aid a host of other lines of research, Pittendrigh said.

“Lice have been used to understand human evolution and migration. They’ve been used to estimate when we started wearing clothing,” he said. “The genome should also help us develop better methods of controlling both head and body lice.”

“Beyond its importance in the context of human health, the body louse genome is of considerable importance to understanding insect evolution,” Berenbaum said. “It is only the second genome sequenced to date of an insect with gradual development – that is, that does not undergo profound anatomical and ecological change as it matures from egg to adult. Although most of the insect species on the planet undergo complete metamorphosis – developing from egg to caterpillar to pupa to adult – in fact gradual metamorphosis is the older developmental program. The body louse genome can provide a baseline for understanding how complete metamorphosis, a key to insect domination of the planet, came to evolve.”

The genome sequencing effort involved researchers at 28 institutions in the U.S., Europe, Australia and South Korea. First author Ewen Kirkness coordinated sequencing and gene identification at the J. Craig Venter Institute. Clark; Lee; Spencer Johnson, of Texas A&M University; Jeanne Romero-Severson, of the University of Notre Dame; Greg Dasch, of the Centers for Disease Control and Prevention; and Pittendrigh wrote the original proposal to obtain funding for the genome sequencing effort from the National Institutes of Health and guided the effort. Evgeny Zdobnov and his team conducted the evolutionary analysis.

The University of Illinois team also included Weilin Sun in the entomology department; crop sciences professor Manfredo Seufferheld; and postdoctoral researcher Hong-Mei Li.

Diana Yates | University of Illinois
Further information:
http://www.illinois.edu

More articles from Life Sciences:

nachricht Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View
22.06.2018 | University of Sussex

nachricht New cellular pathway helps explain how inflammation leads to artery disease
22.06.2018 | Cedars-Sinai Medical Center

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>