Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

How humans lost their scents

19.03.2003


In at least one type of endeavor, humans can’t even begin to compete with their best friends. Dogs can be trained to sniff out drugs and explosives or to track down a crime suspect by smell. Why can’t we do the same? Scientists from the Weizmann Institute of Science and the Max Planck Institute for Evolutionary Anthropology propose an explanation for this ancient quandary.



All mammals, including humans, have about 1,000 genes encoding smell-detecting proteins, or olfactory receptors. These receptors, located in the mucous lining of the nose, identify scents by binding to molecules of odorous substances. However, not all olfactory receptor genes are functioning in all species. It is the percentage of the working olfactory genes that determines the sharpness of smell in animals and humans.

In previous studies, the team of Prof. Doron Lancet of the Weizmann Institute’s Molecular Genetics Department discovered that more than half of these genes in humans contain a mutation that prevents them from working properly. In a new study, published in the March 18, 2003 Proceedings of the National Academy of Sciences (PNAS), the scientists tackled the next question: is the genetic "loss" a relatively old phenomenon affecting all primates, or did it occurr only in humans?


To resolve this issue, the researchers compared the DNA sequences of 50 olfactory receptor genes that are common to humans and different species of apes and monkeys. They found that 54 percent of the genes were impaired in humans, as opposed to only 28 to 36 percent in the other species. This research has made it possible to reconstruct this sense’s deterioration over the course of evolution: apparently, its decline took place within an "evolutionary moment" – only 3 to 5 million years– and occurred four times faster in the branch leading to humans compared to other primates.

The scientists conclude that the drop in the sharpness of smell is a purely Homo sapiens feature. It probably stemmed from the development of the brain in the human direction – a direction that entailed increased emphasis on vision, development of the ability to distinguish colors and the capacity to identify other members of the species by facial appearance rather than by smell.

The research team included Yoav Gilad, a Ph.D. student at the Weizmann Institute’s Feinberg Graduate School who conducted collaborative research at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, his adviser Prof. Doron Lancet, Weizmann graduate student Orna Man, and Prof. Svante Pöäbo, head of the Max Planck Institute in Leipzig.


Prof. Doron Lancet’s research is supported by the Crown Human Genome Center, Alfried Krupp von Bohlen und Halbach Foundation, the Avraham and Yehudit (Judy) Goldwasser Fund, Ms. Emilia Mosseri, London, Mr. James Klutznick, Chicago, IL, Kalman & Ida Wolens Foundation and the Jean-Jacques Brunschwig Memorial Fund.


Alex Smith | EurekAlert!
Further information:
http://www.weizmann.ac.il/

More articles from Life Sciences:

nachricht Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel

nachricht Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>