Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Minimal genome should be twice the size, study shows

30.03.2006
The simplest bacteria need almost twice as many genes to survive than scientists first believed, according to new research published in Nature (30 March 2006).

Bacteria are some of the simplest forms of life and have been studied by scientists trying to identify the smallest collection of genes – or minimal genome – that is needed for maintaining life.

Traditionally scientists have done this by removing, or ‘knocking out’, a series of individual genes from a bacterial genome to see what effect this has on its ability to survive.

They can then infer which genes are essential to the organism, and which are not, to work out which are needed for the minimal genome.

However this knock out approach wrongly removes many of the genes that are essential to the survival of bacteria, according to researchers from Heidelberg (Germany), Manchester (UK), Budapest (Hungary) and Bath (UK).

The researchers made this discovery after developing a new approach to genome modelling which, given the organism’s evolutionary history and knowledge of its surrounding environment, allows them to predict which genes a bacterium’s genome should contain.

“Previous attempts to work out the minimal genome have relied on deleting individual genes in order to infer which genes are essential for maintaining life,” said Professor Laurence Hurst from the Department of Biology and Biochemistry at the University of Bath.

“This knock out approach misses the fact that there are alternative genetic routes, or pathways, to the production of the same cellular product.

“When you knock out one gene, the genome can compensate by using an alternative gene.

“But when you repeat the knock out experiment by deleting the alternative, the genome can revert to the original gene instead.

“Using the knock-out approach you could infer that both genes are expendable from the genome because there appears to be no deleterious effect in both experiments.

“In fact, because there are alternative pathways to the same product, by removing either of the genes you make the other essential for survival; each gene deletion reduces the available space for further reduction of the genome.

”Including these alternative pathways into the minimal genome almost doubles its size.”

The researchers have developed a way of predicting bacterial genome content using two bacteria that have evolved from E.coli.

Buchnera and Wigglesworthia live inside insects in a symbiotic relationship where they provide essential molecules for their hosts in return for essential basic foods.

Since evolving from E.coli, the Buchnera and Wigglesworthia genomes have lost some of the genes that they would otherwise need for survival.

Using computer modelling and knowledge of the present day ecology of the bacteria the researchers were able to model this process of gene loss.

They accurately predicted about 80 per cent of the gene content of the two bacteria, including some of the non-obvious features of their genomes.

“Far from being a cause for disease, the insects need these bacteria to supply them with essential nutrients,” said Professor Hurst.

“In these relatively cosy conditions, Buchnera and Wigglesworthia have lost some of the genes they would otherwise need to produce some of the basic molecules they need to survive.

“Being able to predict the content of a genome based on the ecology of an organism is useful because we could potentially use it to predict gene content at different stages of an organism’s evolution.

“This will help us understand more about how the genome of different organisms have evolved over long periods of time and should also inform attempts by experimentalists to construct minimal genomes by gradual evolution in the laboratory.”

Similar methods might also be used to build a blueprint of a bacterium with desired metabolic properties, for example identifying which genes would a bacterium need to efficiently digest specific waste chemicals.

The research has been supported by the Hungarian Scientific Research Fund, EMBO, the Human Frontier Science Program, DFG and the Biotechnology and Biological Sciences Research Council.

’Chance and necessity in the evolution of minimal metabolic networks’ will be published in Nature on 30 March 2006.

Andrew McLaughlin | alfa
Further information:
http://www.bath.ac.uk/news/articles/releases/minimalgenome290306.html

More articles from Life Sciences:

nachricht New risk factors for anxiety disorders
24.02.2017 | Julius-Maximilians-Universität Würzburg

nachricht Stingless bees have their nests protected by soldiers
24.02.2017 | Johannes Gutenberg-Universität Mainz

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Stingless bees have their nests protected by soldiers

24.02.2017 | Life Sciences

New risk factors for anxiety disorders

24.02.2017 | Life Sciences

MWC 2017: 5G Capital Berlin

24.02.2017 | Trade Fair News

VideoLinks
B2B-VideoLinks
More VideoLinks >>>