"ScienceDaily (Feb. 29, 2012) — It's one of life's special moments: a child finds a fat caterpillar, puts it in a jar with a twig and a few leaves, and awakens one day to find the caterpillar has disappeared and an elegant but apparently lifeless case now hangs from the twig."
How is it that a creature can appear to be a completely different creature multiple times in its lifetime?
"Working with fruit flies rather than butterflies, a team led by Ian and Dianne Duncan of Washington University in St. Louis provides part of the answer in the latest issue of PNAS. Ian Duncan, PhD, is professor of biology in Arts & Sciences; Dianne Duncan is a research associate and director of the Biology Imaging Facility."
Like most insects, fruit flies go through three main phases: the larva, pupae, and adult.
Earlier research has shown that both the larvae and the adults of insect species have similar "signaling systems" patterning them; or "chains of biochemicals that transfer a signal from receptors on the surface of cells to target genes in cell nuclei."
Scientists, however, could not understand how the same systems can both orchestrate the formation of larvae and adults.
Collaborating researchers were able to reveal that a gene expressed only in the pupal stage "redirects signaling systems so that they can activate a different set of target genes than in earlier stages."
The gene itself is controlled by a steroid hormone that turns on a variety of other genes as well.
"So insect metamorphosis, triggered by a hormone, resembles puberty, the human analog of metamorphosis, which is also triggered by hormones."
Scientists, however, could not understand how the same systems can both orchestrate the formation of larvae and adults.
Collaborating researchers were able to reveal that a gene expressed only in the pupal stage "redirects signaling systems so that they can activate a different set of target genes than in earlier stages."
The gene itself is controlled by a steroid hormone that turns on a variety of other genes as well.
"So insect metamorphosis, triggered by a hormone, resembles puberty, the human analog of metamorphosis, which is also triggered by hormones."
Continue reading this article. ScienceDaily expresses the specified details of this phenomenal change that occurs in insects: facts that are far too complicated for me to express without flat-out plagiarizing.
No comments:
Post a Comment