GAINESVILLE, Fla. A new University of Florida study shows genomes of a recently formed plant species to be highly unstable, a phenomenon that may have far-reaching evolutionary consequences.
Published online this week in the Proceedings of the National Academy of Sciences, the study is the first to document chromosomal variation in natural populations of a recently formed plant species following whole genome doubling, or polyploidy. Because many agricultural crops are young polyploids, the data may be used to develop plants with higher fertility and yields. Polyploid crops include wheat, corn, coffee, apples, broccoli and some rice species.
"It could be occurring in other polyploids, but this sort of methodology just hasn't been applied to many plant species," said study co-author Pam Soltis, distinguished professor and curator of molecular systematics and evolutionary genetics at the Florida Museum of Natural History on the UF campus. "So it may be that lots of polyploids including our crops may not be perfect additive combinations of the two parents, but instead have more chromosomes from one parent or the other."
Researchers analyzed about 70 Tragopogon miscellus plants, a species in the daisy family that originated in the northwestern U.S. about 80 years ago. The new species formed naturally when two plants introduced from Europe mated to produce a hybrid offspring, and hybridization was followed by polyploidy.
Using a technique called "chromosome painting" to observe the plants' DNA, UF postdoctoral researcher and lead author Michael Chester discovered that while whole genome doubling initially results in a new species containing 12 chromosomes from each parent, numbers subsequently vary among many plants.
The paints are made by attaching different dyes to DNA of the two parent species. Once the dye is applied, there is a match between the DNA of the paint and of the chromosome. Under a microsc
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University of Florida