New research suggests that natural selection, famous for rewarding advantageous differences in organisms, can also preserve similarities. The researchers worked with a plant called wild radish and its stamens, or pollen-producing parts, two of which are short and four are long. Roughly 55 million years ago, wild radish ancestors had stamens of equal length. The team selectively bred -- or artificially selected -- wild radish to reduce the difference in stamen length and return the plant to a more ancestral look. This shows that today's wild radish and, likely, its family members still have the requisite genetic variability to evolve, but natural selection is preserving its different stamen lengths.
