Columbines: so different, yet so much alike.
Throughout North America, four or five kinds with drooping red flowers atrract hummingbirds. One of Colorado's columbines greets moth pollinators with upturned yellow petals and spurs; another is blue and white. In Europe, a purple-blue version with a particularly stylish spur lures buumblebees. In Siberia, files pollinate a culumbine with pale green and brownish-purple petals.
Such distribution and variety suggest that this genus. Aquilegia, has been around a while. However, these species their genes are fairly compatible and therefore that they share a recent ancenstor.
A genetic study of more than 14 columbine species bears out this latter notion, says Scott A. Hodges, a botanist and genetricist at the University of Georgia in Athens. He and George colleague Michael L. Arnold obtained two species from Europe, two from Asia, and 10 from North America. They analyzed DNA from the chloroplast -- the plant cell's photosynthetic center -- and from the cell nucleus of each species.
then they performed similar analyses for four species of Thalictrum, commonly called meadow rue, and Isopyrum, or false rue anemone, and a few other members of the buttercup family, of which the columbine is a member.
The Thalictrum and isoprym and 3 to 45 times the genetic variation of the columbine species, Hodges and Arnold report in the May 24 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES.
That the columbine failed to show much difference in DNA from either the chloroplast or the nucleus strengthens the argument that this flower has evolved recently, Hodges adds. The data also suggest that European and Asian columbines predate North Amerirican species.
he suspectes the nectar spur provided the flower with the means for this rapid diversification, or radiation. The color, shape, and length of the spur makes the nectar deep inside accessible to certain animals, enabling columbines to specialize and consequently diversify based on what pollinates them.
Until now, scientists have studied rapid, recent radiation in isolated lakes or islands, such as Hawaii. Supposedly, those restricted habitats encourage radioation because they offer new arrivals lots of new food and habitat opportunities. "This study says you don't have to have that kind of setting," Hodges says. Columbines spread and changed throughout the whole world, in particular throughout North American. "There may be other factors that we haven't through about," he adds.
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|Title Annotation:||study explains rapid diversification of Aquilegia species|
|Date:||May 28, 1994|
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