Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

History of human cannibalism eats away at researchers

05.01.2006


New study challenges previous reports of cannibalism as a worldwide selective force



In a new study published by the journal Genome Research, a team of scientists reports that ’mad cow’-like diseases have not been a major force in human history, nor have been cannibalistic rituals that are known to be associated with disease transmission. Prof. Jaume Bertranpetit, a scientist at the Universitat Pompeu Fabra, and his colleagues used a fresh set of genetic data to show that balancing selection associated with cannibalism has not been a major selective driving force on the prion protein gene, as has recently been proposed. Their work also has important scientific implications for researchers using a specific class of DNA markers called SNPs (single nucleotide polymorphisms) to examine genetic associations with diseases or to evaluate historical patterns of human migration.

The prion protein gene (PRNP) encodes a protein that can abnormally fold and amass in brain tissues to cause fatal neurodegenerative diseases such as mad cow disease. These diseases are cumulatively known as transmissible spongiform encephalopathies (TSEs) and in humans, include CJD (Creutzfeldt-Jakob disease) and kuru. Kuru is confined to a human population in Papua-New Guinea and is transmitted by cannibalism at ritualistic mortuary feasts.


A high-profile study published nearly three years ago suggested that individuals who were heterozygous for a common polymorphism in the PRNP gene were relatively resistant to the disease. Over time, homozygotes who participated in the cannibalistic rituals purportedly diminished in numbers due to their increased susceptibility to kuru. This indicated that cannibalism conferred an effect of balancing selection on the PRNP gene throughout human history.

Bertranpetit and his colleagues sequenced 2,378 base pairs of the PRNP gene in 174 individuals; in addition, they genotyped two SNPs (or single nucleotide polymorphisms) from the PRNP gene in 1000 individuals from populations worldwide. They identified 28 different haplotypes – or combinations of DNA variants – in the PRNP gene and used this data to assess the ages of the mutations, to identify geographic patterns of variation, and to evaluate selective forces that have potentially influenced these patterns.

"In contrast to the previous study, which concluded that variation in the PRNP gene was strongly skewed toward intermediate frequency variants, our results showed that there was, in fact, a deficit of intermediate frequency variants," says Bertranpetit. "Our results are consistent with a complex history of episodic or fluctuating selection, including positive selection, purifying selection, and possibly even short periods of balancing selection."

On a more technical note, the study cautions researchers involved in SNP-based population genetics studies. The work is one of the first to empirically demonstrate how SNP ascertainment can introduce a strong bias in population genetics studies and severely affect the conclusions. Bertranpetit and his colleagues point out that at a time when a flood of ascertained SNP data is being generated, it is essential that SNP ascertainment be taken into consideration in data analyses.

The first author on the study is Dr. Marta Soldevila, who completed her Ph.D. at the Universitat Pompeu Fabra and performed a substantial part of the sequencing work at DeCODE Genetics (Reykjavik, Iceland).

Maria Smit | EurekAlert!
Further information:
http://www.cshl.edu

More articles from Studies and Analyses:

nachricht Innovative genetic tests for children with developmental disorders and epilepsy
11.07.2018 | Christian-Albrechts-Universität zu Kiel

nachricht Oxygen loss in the coastal Baltic Sea is “unprecedentedly severe”
05.07.2018 | European Geosciences Union

All articles from Studies and Analyses >>>

The most recent press releases about innovation >>>

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

Im Focus: First evidence on the source of extragalactic particles

For the first time ever, scientists have determined the cosmic origin of highest-energy neutrinos. A research group led by IceCube scientist Elisa Resconi, spokesperson of the Collaborative Research Center SFB1258 at the Technical University of Munich (TUM), provides an important piece of evidence that the particles detected by the IceCube neutrino telescope at the South Pole originate from a galaxy four billion light-years away from Earth.

To rule out other origins with certainty, the team led by neutrino physicist Elisa Resconi from the Technical University of Munich and multi-wavelength...

Im Focus: Magnetic vortices: Two independent magnetic skyrmion phases discovered in a single material

For the first time a team of researchers have discovered two different phases of magnetic skyrmions in a single material. Physicists of the Technical Universities of Munich and Dresden and the University of Cologne can now better study and understand the properties of these magnetic structures, which are important for both basic research and applications.

Whirlpools are an everyday experience in a bath tub: When the water is drained a circular vortex is formed. Typically, such whirls are rather stable. Similar...

Im Focus: Breaking the bond: To take part or not?

Physicists working with Roland Wester at the University of Innsbruck have investigated if and how chemical reactions can be influenced by targeted vibrational excitation of the reactants. They were able to demonstrate that excitation with a laser beam does not affect the efficiency of a chemical exchange reaction and that the excited molecular group acts only as a spectator in the reaction.

A frequently used reaction in organic chemistry is nucleophilic substitution. It plays, for example, an important role in in the synthesis of new chemical...

Im Focus: New 2D Spectroscopy Methods

Optical spectroscopy allows investigating the energy structure and dynamic properties of complex quantum systems. Researchers from the University of Würzburg present two new approaches of coherent two-dimensional spectroscopy.

"Put an excitation into the system and observe how it evolves." According to physicist Professor Tobias Brixner, this is the credo of optical spectroscopy....

Im Focus: Chemical reactions in the light of ultrashort X-ray pulses from free-electron lasers

Ultra-short, high-intensity X-ray flashes open the door to the foundations of chemical reactions. Free-electron lasers generate these kinds of pulses, but there is a catch: the pulses vary in duration and energy. An international research team has now presented a solution: Using a ring of 16 detectors and a circularly polarized laser beam, they can determine both factors with attosecond accuracy.

Free-electron lasers (FELs) generate extremely short and intense X-ray flashes. Researchers can use these flashes to resolve structures with diameters on the...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Leading experts in Diabetes, Metabolism and Biomedical Engineering discuss Precision Medicine

13.07.2018 | Event News

Conference on Laser Polishing – LaP: Fine Tuning for Surfaces

12.07.2018 | Event News

11th European Wood-based Panel Symposium 2018: Meeting point for the wood-based materials industry

03.07.2018 | Event News

 
Latest News

Subaru Telescope helps pinpoint origin of ultra-high energy neutrino

16.07.2018 | Physics and Astronomy

Barium ruthenate: A high-yield, easy-to-handle perovskite catalyst for the oxidation of sulfides

16.07.2018 | Life Sciences

New research calculates capacity of North American forests to sequester carbon

16.07.2018 | Earth Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>