Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Although our genetics differ significantly, we all look alike...

27.01.2009
The genetic variation within a species can be significant, but very little of that variation results in clear differences in morphology or other phenotypes.

Much of the diversity remains hidden ‘under the surface’ in buffered form. This has been revealed by research conducted by the University of Groningen, Wageningen University and Research Centre (both Netherlands) and the British research centre Rothamsted Research. The research was published on 25 January 2009 in Nature Genetics.

The researchers crossed two ecotypes of Arabidopsis and investigated the offspring for molecular and phenotypic differences, for example the number of proteins and metabolites that are formed and susceptibility to disease. It turned out that of the hundreds of thousands of differences in the DNA, only six ‘hotspots’ had major molecular and phenotypic effects.

Variation
The DNA of the two crossed ecotypes of Arabidopsis thaliana, a small plant that serves as a model organism in genetic research, differs on no fewer than 500,000 points, i.e. there is significant genetic variation. Of the offspring of the crossbreeding, 162 plants were investigated on 139 external characteristics (classic phenotypic traits such as the height of the plant, flowering time or resistance to disease) and 40,000 molecular traits. The latter category covers the products of the genes, i.e. the transcripts and proteins formed in the plant cell and the healthy or toxic compounds (metabolites) that these proteins generate in their turn. Many of these traits show substantial phenotypic variation.
Clusters
Research leader Prof. Ritsert Jansen: ‘You’d expect the mutations – the genetic causes of these phenotypic differences – to be evenly divided over the DNA, that they would be spread out over the whole genome, in a manner of speaking. This was clearly not the case in this experiment. We could point out exactly six areas in the genome where the genetic causes of thousands of differences were located. In other words, the genetic causes turned out to be clustered into six hotspots. The other 500,000 mutations in the genome only had a relatively very minor influence.’
Buffering
As described in the publication, this is a type of buffering – the 500,000 genetic differences do influence the activity of thousands of genes, but that diversity gradually diminishes the further you move away from the genetic source, the DNA; it is buffered. Eventually, only a small number of hotspots remain and these cause phenotypic differences at the highest levels, in metabolites and classic phenotypic traits. ‘The genetic variation is significantly present deep in the cell but is muffled more and more the further you move towards the outside’, Jansen explains.
Evolution
Although buffering has a muffling effect on the evolution of a species, it certainly does not hinder it. Jansen: ‘I’d say that it’s lucky there’s buffering. Just imagine if each of the 500,000 differences was immediately expressed in the next generation. From the point of view of the “robustness” of a species, it’s necessary that the offspring do not vary too dramatically. But if there’s a change in the environment that requires an evolutionary adaptation, then the necessary genetic variation is ready and waiting.’
Hotspots
The discovery means that life scientists should in particular examine the hotspots in the genome when searching for the causes of genetic disorders. In that regard the results of the current research agree with the results of Prof. Cisca Wijmenga of the University Medical Center Groningen, which was published in Nature Reviews Genetics in December. Her research revealed that only a limited number of hotspot genes are involved in the development of numerous immune-related diseases, such as type 1 diabetes, coeliac disease, Crohn’s disease and rheumatoid arthritis. Just like Arabidopsis, people differ from each other in millions of positions in their genome, but it’s the genotype in the hotspots that is the most relevant. ‘When it comes down to it, we are more similar to each other than the major differences in genome sequences suggest.’

Jos Speekman | alfa
Further information:
http://www.rug.nl

More articles from Life Sciences:

nachricht Bare bones: Making bones transparent
27.04.2017 | California Institute of Technology

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

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

Bare bones: Making bones transparent

27.04.2017 | Life Sciences

Study offers new theoretical approach to describing non-equilibrium phase transitions

27.04.2017 | Physics and Astronomy

From volcano's slope, NASA instrument looks sky high and to the future

27.04.2017 | Earth Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>