Model variation

© Dr. Jeremy Burgess / Photo Researchers, Inc.

To better understand how evolutionary pressures have helped shape genetic variation in Arabidopsis thaliana, Detlef Weigel from the Salk Institute for Biological Studies in La Jolla, Calif., and colleagues used high-density oligonucleotide arrays to look at single nucleotide polymorphisms of 20 diverse strains of the plant. ¹ The group found that, since 2000, about 4% of the genome changed significantly or was deleted.

The researchers found that genes involved in ribosomal function and transcriptional regulation were not highly variable among strains. Genes involved in pathogen resistance, however, especially those from the NB-LRR gene family, were highly variable among strains, making it "certainly possible that evolutionary pressure by pathogens helped shape the diversity of genes," says Julin Maloof, plant biologist at the University of California, Davis, a member of the Faculty of 1000, and also a former postdoc of the study's lead author.

"Our challenge is going to be to understand what effect this diversity has on the plant," in terms of its survival and appearance, Maloof says. "We can look through this dataset and see which genes undergo the most changes," which, he added, may suggest certain genes as study targets of plant responses to varying conditions, such as light and water exposure.