( ugh the series of nymphal stages she ...)Gene needed for butterfly transformation also key for insects like grasshoppers

Erezyilmaz is the lead author of a paper describing the findings, published online Tuesday in the Proceedings of the National Academy of Sciences. The work was done in the UW laboratories of biology professors James Truman and Lynn Riddiford, who are co-authors of the paper, and was underwritten by grants from the National Science Foundation and the National Institutes of Health.

Genes regulate how an organism grows and changes physically as it develops. The broad gene encodes a protein that attaches itself to a specific region of a DNA chain and controls which other genes will be copied. The researchers suspect that broad must be present for the physical changes contained in those areas of DNA to be expressed. Suppressing broad prevents the changes from occurring.

"Humans don't have the broad gene, but if they did and you suppressed it you'd have a baby that might grow to 6 feet tall but would still have the body proportions of a baby," Truman said. "It would still have the large head and the stubby legs."

A substance called juvenile hormone is present at each step of nymph development in insects that do not experience complete metamorphosis, and the researchers found that juvenile hormone correlates with the expression of the broad gene during the nymphal stage. Juvenile hormone disappears in the last nymphal stage and the broad gene is no longer expressed, allowing the insect to make the final transition to adulthood.

"This is the first time that anyone has seen the broad gene appear in the development of insects having incomplete metamorphosis," said Riddiford. "It appears in the late embryonic stage and stays throughout nymphal life, then disappears when the insect transforms to an adult."