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 Good preparation is half the digestion
15.11.2018 | Max-Planck-Institut für Stoffwechselforschung

nachricht How the gut ‘talks’ to brown fat
16.11.2018 | Technische Universität München

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: A Chip with Blood Vessels

Biochips have been developed at TU Wien (Vienna), on which tissue can be produced and examined. This allows supplying the tissue with different substances in a very controlled way.

Cultivating human cells in the Petri dish is not a big challenge today. Producing artificial tissue, however, permeated by fine blood vessels, is a much more...

Im Focus: A Leap Into Quantum Technology

Faster and secure data communication: This is the goal of a new joint project involving physicists from the University of Würzburg. The German Federal Ministry of Education and Research funds the project with 14.8 million euro.

In our digital world data security and secure communication are becoming more and more important. Quantum communication is a promising approach to achieve...

Im Focus: Research icebreaker Polarstern begins the Antarctic season

What does it look like below the ice shelf of the calved massive iceberg A68?

On Saturday, 10 November 2018, the research icebreaker Polarstern will leave its homeport of Bremerhaven, bound for Cape Town, South Africa.

Im Focus: Penn engineers develop ultrathin, ultralight 'nanocardboard'

When choosing materials to make something, trade-offs need to be made between a host of properties, such as thickness, stiffness and weight. Depending on the application in question, finding just the right balance is the difference between success and failure

Now, a team of Penn Engineers has demonstrated a new material they call "nanocardboard," an ultrathin equivalent of corrugated paper cardboard. A square...

Im Focus: Coping with errors in the quantum age

Physicists at ETH Zurich demonstrate how errors that occur during the manipulation of quantum system can be monitored and corrected on the fly

The field of quantum computation has seen tremendous progress in recent years. Bit by bit, quantum devices start to challenge conventional computers, at least...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

“3rd Conference on Laser Polishing – LaP 2018” Attracts International Experts and Users

09.11.2018 | Event News

On the brain’s ability to find the right direction

06.11.2018 | Event News

European Space Talks: Weltraumschrott – eine Gefahr für die Gesellschaft?

23.10.2018 | Event News

 
Latest News

Massive impact crater from a kilometer-wide iron meteorite discovered in Greenland

15.11.2018 | Earth Sciences

When electric fields make spins swirl

15.11.2018 | Physics and Astronomy

Discovery of a cool super-Earth

15.11.2018 | Physics and Astronomy

VideoLinks
Science & Research
Overview of more VideoLinks >>>