One Species, Many Genomes: How Plants Adapt to Local Environments

How do you distinguish between a wild variety of Arabidopsis thaliana and a lab strain? Just look at their genomes. Scientists in Germany and the United States were surprised that on average, every 180th DNA building block of the Arabidopsis genome is variable. And about four percent of the reference genome (the sequenced genome of a lab strain of the plant) either looks very different in the wild varieties, or cannot be found at all. In their study, the researchers compared the genetic material of 19 wild strains with that of the genome of the lab strain. They examined every one of the roughly 120 million building blocks of the genome.
Detailed analyses showed that genes for basic cellular functions such as protein production or gene regulation rarely vary. Genes that are important for the interaction with other organisms, on the other hand, such as those responsible for defense against pathogens or infections, are much more variable.

"The genetic variability appears to reflect adaptation of local circumstances," says Detlef Weigel from the Max Planck Institute for Developmental Biology. It is likely that such variable genes allow plants to withstand dry or wet, hot or cold conditions, or make use of short or long growing seasons. Weigel is already collaborating with the International Rice Research Institute (IRRI) in the Philippines to apply the methods and experience gathered with Arabidopsis to twenty different rice varieties.

Read the news article at http://www.mpg.de/english/illustrationsDocumentation/documentation/pressReleases/2007/pressRelease
20070718/index.html