Genome duplication and the limits of evolution
|May 6, 2011||Posted by News under Evolution, Genomics|
“Genome Duplication Encourages Rapid Adaptation of Plants” (ScienceDaily, May 4, 2011)
While nearly all animals have two sets of chromosomes — one set inherited from the maternal parent and the other inherited from the paternal parent — many plants are polyploids, meaning they have four or more chromosome sets. “Some botanists have wondered if polyploids have novel features that allow them to survive environmental change or colonize new habitats,” says Assistant Professor Justin Ramsey. “But this idea had not been rigorously tested.”
Forcing duplication on wild plants (instead of the centuries old practice of forcing it on tame ones) produced quick results, as it does in tame ones:
Ramsey compared the performance of the transplanted yarrows and found that the hexaploid mutants had a 70 percent survival advantage over their tetraploid siblings. Because the tetraploid and hexaploid plants had a shared genetic background, the difference of survivorship was directly attributable to the number of chromosome sets rather than the DNA sequences contained on the chromosomes.
Those who think they have solved the abominable mystery of flowering plants tend to forget that the mega chrome types are just better adapted, not new species. Some sources think it best to wait 100 years to see if they dominate or just breed back into the common run (cf escaped pigs.)