Mass copying of genes speeds up evolution

October 31, 2006

In the latest issue of PNAS, Proceedings of the National Academy of Sciences, a Swedish-American team of researchers show how selective gene amplification-­mass copying of a specific gene­-can increase the speed with which organisms adapt to their environment.

All organisms can amplify parts of their DNA under certain conditions, and the variants that have an increased amount of one special gene can gain survival advantages when they are exposed to various types of external conditions, such as stress in the form of antibiotics (bacteria), chemotherapy (humans), or insecticides (insects).

In this study the researchers show that the bacteria Salmonella typhimurium uses several different mechanisms to increase the number of copies of a gene that helps the cell use the sugar lactose as a source of nourishment.

“When the bacterium’s gene for making use of lactose is inefficient, that is, when the bacterium has an ineffective enzyme for breaking down lactose, mutant bacteria are favored instead, with up to a hundred-fold rise in the number of copies of the gene,” says Professor Dan Andersson, one of those behind the study.

This has two consequences: on the one hand, the bacterium manages to grow on lactose because the amount of the inefficient enzyme increases and, on the other hand, the chances increase that the bacterium will develop a mutation in one of these 100 identical genes leading to an improvement in the enzyme function. The scientists also show that amplification proceeds stepwise: first, a large region is duplicated and then smaller regions within that region are amplified to high numbers of copies. According to Dan Andersson, it is probably much more common than was previously thought, which is extremely exciting.

“And they are important, since this means that evolutionary changes can take place at a considerably higher speed. One reason the extent of this has been underestimated is their inherent instability, which makes them difficult to study in laboratory experiments.”

Source: Uppsala Universitet

Explore further: Decades of research yield natural dairy thickener with probiotic potential

Related Stories

Bacteria become 'genomic tape recorders'

November 13, 2014

MIT engineers have transformed the genome of the bacterium E. coli into a long-term storage device for memory. They envision that this stable, erasable, and easy-to-retrieve memory will be well suited for applications such ...

Bacteria can plan ahead

June 17, 2009

Bacteria can anticipate a future event and prepare for it, according to new research at the Weizmann Institute of Science. In a paper that appeared today in Nature, Prof. Yitzhak Pilpel, doctoral student Amir Mitchell and ...

Recommended for you

Researchers build bacteria's photosynthetic engine

July 29, 2015

Nearly all life on Earth depends on photosynthesis, the conversion of light energy into chemical energy. Oxygen-producing plants and cyanobacteria perfected this process 2.7 billion years ago. But the first photosynthetic ...

Yarn from slaughterhouse waste

July 29, 2015

ETH researchers have developed a yarn from ordinary gelatine that has good qualities similar to those of merino wool fibers. Now they are working on making the yarn even more water resistant.

Scientists unlock secrets of stars through aluminium

July 29, 2015

Physicists at the University of York have revealed a new understanding of nucleosynthesis in stars, providing insight into the role massive stars play in the evolution of the Milky Way and the origins of the Solar System.

Studies reveal details of error correction in cell division

July 29, 2015

Cell biologists led by Thomas Maresca at the University of Massachusetts Amherst, with collaborators elsewhere, report an advance in understanding the workings of an error correction mechanism that helps cells detect and ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.