Speed of evolution faster than thought, say scientists (Roundup)

Jan 1, 2010, 13:00 GMT

Berlin - A team of German and US scientists has discovered that genetic mutation - the basic process of evolution - occurs much faster than previously thought, according to a study published Friday.

The team of researchers from the Max Planck Institute for Molecular Biology in Tuebingen and the University of Indiana studied genome mutation in a species of cress (Arabidopsis thaliana), and found that each gene in the plant will mutate on average once in every 143 million generations.

Genomes are the complete set of genetic information for any organism, consisting of individual genes found in DNA.

'While the long-term effects of genome mutations are quite well understood, we did not know how often new mutations arise in the first place,' project leader Detlef Weigel of the Max Planck Institute said in a press statement.

The discovery means that for many plant species, whose millions of individual members produce thousands of seeds with each generation, an entire genome mutation can occur within a relatively short space of time.

'Evolution reveals itself only after thousands, not millions of years,' Weigel said.

Such a rate of genetic change can explain how species adapt to changing circumstances quickly, and the study gives the example of weeds becoming resistant to specific herbicides within just a few generations.

The team used new methods to track all the genetic changes in five 'lines' (plants with common ancestors) of Arabidopsis thaliana over 30 generations. In the final generation they searched for differences to the original plants.

'To ferret out where the genome had changed was only possible because of new methods that allowed us to screen the entire genome with high precision and in a very short time,' Weigel said.

The team said that the same speed of genetic change could in theory be expected in human DNA, meaning that with six billion people on earth each form of human gene would be permanently mutating somewhere on the planet.

'If you apply our findings to humans, then each of us will have in the order of 60 new mutations that were not present in our parents. Everything that is genetically possible is being tested in a very short period,' said Indiana University's Michael Lynch.

Max Planck Society: www.mpg.de