In “Climate-Shaped Arabidopsis Genome” (The Scientist, October 6, 2011), Kerry Grens tells us, “Two genome-wide studies, backed up by field experiments, identify SNPs that correlate with Arabidopsis fitness in various climates.”:
The papers, published today (October 6) in Science, agree that the plant has adapted to changing conditions, but there’s no consensus yet on the primary mechanism. Schmitt’s study found that standing variation—the polymorphisms already in the population—played a major role, while the other paper found greater evidence of selective sweeps by newly introduced mutations.
Surprisingly to Schmitt, “the genetic basis of fitness is almost entirely different in different climates.” She and her colleagues found that SNPs that helped a plant in one climate were not necessarily deleterious in another climate. “So it’s not a particular gene, but entirely different genes that seem to be responsible for high performance at different sites,” she said.
That should make research more enlightening, though not easier.