"We've done a lot of experiments, described in this paper, that show none of the simple explanations account for this skipping of generations by an inherited trait."
The scientists kept the plants in isolation so they couldn't accidentally crossbreed with plants that didn't have the mutated gene, called hothead, that causes organ fusion like that seen in the flowers. The researchers used molecular markers - bits of DNA that help identify and locate genes in organisms - to determine whether a plant carried normal or mutant copies of the genes.
"It seems that these hothead-containing plants keep a cryptic copy of everything that was in the previous generation, even though it doesn't show up in the DNA, it's not in the chromosome," Pruitt said. "Some other type of gene sequence information that we don't really understand yet is modifying the inherited traits."
Although the hothead gene tipped the researchers off to this unconventional inheritance cycle, Pruitt believes that this particular DNA sequence is just a trigger for the phenomenon. He suspects that a number of other genes and the proteins they produce are involved in activating this process.
"We need to understand more about the molecular mechanics of how this process works," Pruitt said. "Then we will know exactly what role this gene plays."
Pruitt's team already knows that animals don't have hothead genes, either normal or mutated, so the scientists must investigate which genes might affect this novel inheritance in both plants and animals.
"There are probably a lot of other triggers yet to be discovered, and this mechanism for inheritance ma
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Contact: Susan A. Steeves
ssteeves@purdue.edu
765-496-7481
Purdue University
22-Mar-2005